diff --git a/gomock/internal/mock_gomock/mock_matcher.go b/gomock/internal/mock_gomock/mock_matcher.go
index fb0693c..2558913 100644
--- a/gomock/internal/mock_gomock/mock_matcher.go
+++ b/gomock/internal/mock_gomock/mock_matcher.go
@@ -19,6 +19,7 @@ import (
 type MockMatcher struct {
 	ctrl     *gomock.Controller
 	recorder *MockMatcherMockRecorder
+	isgomock struct{}
 }
 
 // MockMatcherMockRecorder is the mock recorder for MockMatcher.
@@ -38,11 +39,6 @@ func (m *MockMatcher) EXPECT() *MockMatcherMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockMatcher) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Matches mocks base method.
 func (m *MockMatcher) Matches(arg0 any) bool {
 	m.ctrl.T.Helper()
diff --git a/gomock/mock_test.go b/gomock/mock_test.go
index aa632a4..8b3ca38 100644
--- a/gomock/mock_test.go
+++ b/gomock/mock_test.go
@@ -19,6 +19,7 @@ import (
 type MockFoo struct {
 	ctrl     *gomock.Controller
 	recorder *MockFooMockRecorder
+	isgomock struct{}
 }
 
 // MockFooMockRecorder is the mock recorder for MockFoo.
@@ -38,11 +39,6 @@ func (m *MockFoo) EXPECT() *MockFooMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockFoo) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Bar mocks base method.
 func (m *MockFoo) Bar(arg0 string) string {
 	m.ctrl.T.Helper()
diff --git a/gomock/string.go b/gomock/string.go
index 6daf917..ec4ca7e 100644
--- a/gomock/string.go
+++ b/gomock/string.go
@@ -1,25 +1,36 @@
 package gomock
 
-import "fmt"
-
-type mockInstance interface {
-	ISGOMOCK() struct{}
-}
-type mockedStringer interface {
-	fmt.Stringer
-	mockInstance
-}
+import (
+	"fmt"
+	"reflect"
+)
 
 // getString is a safe way to convert a value to a string for printing results
 // If the value is a a mock, getString avoids calling the mocked String() method,
 // which avoids potential deadlocks
 func getString(x any) string {
-	switch v := x.(type) {
-	case mockedStringer:
-		return fmt.Sprintf("%T", v)
-	case fmt.Stringer:
-		return v.String()
-	default:
-		return fmt.Sprintf("%v", v)
+	if isGeneratedMock(x) {
+		return fmt.Sprintf("%T", x)
+	}
+	if s, ok := x.(fmt.Stringer); ok {
+		return s.String()
+	}
+	return fmt.Sprintf("%v", x)
+}
+
+// isGeneratedMock checks if the given type has a "isgomock" field,
+// indicating it is a generated mock.
+func isGeneratedMock(x any) bool {
+	typ := reflect.TypeOf(x)
+	if typ == nil {
+		return false
+	}
+	if typ.Kind() == reflect.Ptr {
+		typ = typ.Elem()
+	}
+	if typ.Kind() != reflect.Struct {
+		return false
 	}
+	_, isgomock := typ.FieldByName("isgomock")
+	return isgomock
 }
diff --git a/mockgen/internal/tests/add_generate_directive/mock.go b/mockgen/internal/tests/add_generate_directive/mock.go
index 1594548..2cd489e 100644
--- a/mockgen/internal/tests/add_generate_directive/mock.go
+++ b/mockgen/internal/tests/add_generate_directive/mock.go
@@ -21,6 +21,7 @@ import (
 type MockFoo struct {
 	ctrl     *gomock.Controller
 	recorder *MockFooMockRecorder
+	isgomock struct{}
 }
 
 // MockFooMockRecorder is the mock recorder for MockFoo.
@@ -40,11 +41,6 @@ func (m *MockFoo) EXPECT() *MockFooMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockFoo) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Bar mocks base method.
 func (m *MockFoo) Bar(arg0 []string, arg1 chan<- Message) {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/const_array_length/mock.go b/mockgen/internal/tests/const_array_length/mock.go
index 844a9ab..c1ec7f8 100644
--- a/mockgen/internal/tests/const_array_length/mock.go
+++ b/mockgen/internal/tests/const_array_length/mock.go
@@ -19,6 +19,7 @@ import (
 type MockI struct {
 	ctrl     *gomock.Controller
 	recorder *MockIMockRecorder
+	isgomock struct{}
 }
 
 // MockIMockRecorder is the mock recorder for MockI.
@@ -38,11 +39,6 @@ func (m *MockI) EXPECT() *MockIMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockI) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Bar mocks base method.
 func (m *MockI) Bar() [2]int {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/copyright_file/mock.go b/mockgen/internal/tests/copyright_file/mock.go
index cd71bea..8408cda 100644
--- a/mockgen/internal/tests/copyright_file/mock.go
+++ b/mockgen/internal/tests/copyright_file/mock.go
@@ -24,6 +24,7 @@ import (
 type MockEmpty struct {
 	ctrl     *gomock.Controller
 	recorder *MockEmptyMockRecorder
+	isgomock struct{}
 }
 
 // MockEmptyMockRecorder is the mock recorder for MockEmpty.
@@ -42,8 +43,3 @@ func NewMockEmpty(ctrl *gomock.Controller) *MockEmpty {
 func (m *MockEmpty) EXPECT() *MockEmptyMockRecorder {
 	return m.recorder
 }
-
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockEmpty) ISGOMOCK() struct{} {
-	return struct{}{}
-}
diff --git a/mockgen/internal/tests/custom_package_name/greeter/greeter_mock_test.go b/mockgen/internal/tests/custom_package_name/greeter/greeter_mock_test.go
index 1eaa93c..f87a3c3 100644
--- a/mockgen/internal/tests/custom_package_name/greeter/greeter_mock_test.go
+++ b/mockgen/internal/tests/custom_package_name/greeter/greeter_mock_test.go
@@ -20,6 +20,7 @@ import (
 type MockInputMaker struct {
 	ctrl     *gomock.Controller
 	recorder *MockInputMakerMockRecorder
+	isgomock struct{}
 }
 
 // MockInputMakerMockRecorder is the mock recorder for MockInputMaker.
@@ -39,11 +40,6 @@ func (m *MockInputMaker) EXPECT() *MockInputMakerMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockInputMaker) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // MakeInput mocks base method.
 func (m *MockInputMaker) MakeInput() client.GreetInput {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/defined_import_local_name/mock.go b/mockgen/internal/tests/defined_import_local_name/mock.go
index 9648c8f..810f364 100644
--- a/mockgen/internal/tests/defined_import_local_name/mock.go
+++ b/mockgen/internal/tests/defined_import_local_name/mock.go
@@ -21,6 +21,7 @@ import (
 type MockWithImports struct {
 	ctrl     *gomock.Controller
 	recorder *MockWithImportsMockRecorder
+	isgomock struct{}
 }
 
 // MockWithImportsMockRecorder is the mock recorder for MockWithImports.
@@ -40,11 +41,6 @@ func (m *MockWithImports) EXPECT() *MockWithImportsMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockWithImports) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Method1 mocks base method.
 func (m *MockWithImports) Method1() b_mock.Buffer {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/dot_imports/mock.go b/mockgen/internal/tests/dot_imports/mock.go
index 20d27d3..e941ee1 100644
--- a/mockgen/internal/tests/dot_imports/mock.go
+++ b/mockgen/internal/tests/dot_imports/mock.go
@@ -22,6 +22,7 @@ import (
 type MockWithDotImports struct {
 	ctrl     *gomock.Controller
 	recorder *MockWithDotImportsMockRecorder
+	isgomock struct{}
 }
 
 // MockWithDotImportsMockRecorder is the mock recorder for MockWithDotImports.
@@ -41,11 +42,6 @@ func (m *MockWithDotImports) EXPECT() *MockWithDotImportsMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockWithDotImports) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Method1 mocks base method.
 func (m *MockWithDotImports) Method1() Request {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/empty_interface/mock.go b/mockgen/internal/tests/empty_interface/mock.go
index 6656e40..bff5ea1 100644
--- a/mockgen/internal/tests/empty_interface/mock.go
+++ b/mockgen/internal/tests/empty_interface/mock.go
@@ -17,6 +17,7 @@ import (
 type MockEmpty struct {
 	ctrl     *gomock.Controller
 	recorder *MockEmptyMockRecorder
+	isgomock struct{}
 }
 
 // MockEmptyMockRecorder is the mock recorder for MockEmpty.
@@ -35,8 +36,3 @@ func NewMockEmpty(ctrl *gomock.Controller) *MockEmpty {
 func (m *MockEmpty) EXPECT() *MockEmptyMockRecorder {
 	return m.recorder
 }
-
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockEmpty) ISGOMOCK() struct{} {
-	return struct{}{}
-}
diff --git a/mockgen/internal/tests/exclude/mock.go b/mockgen/internal/tests/exclude/mock.go
index 4f219ae..304e018 100644
--- a/mockgen/internal/tests/exclude/mock.go
+++ b/mockgen/internal/tests/exclude/mock.go
@@ -19,6 +19,7 @@ import (
 type MockGenerateMockForMe struct {
 	ctrl     *gomock.Controller
 	recorder *MockGenerateMockForMeMockRecorder
+	isgomock struct{}
 }
 
 // MockGenerateMockForMeMockRecorder is the mock recorder for MockGenerateMockForMe.
@@ -38,11 +39,6 @@ func (m *MockGenerateMockForMe) EXPECT() *MockGenerateMockForMeMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockGenerateMockForMe) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // B mocks base method.
 func (m *MockGenerateMockForMe) B() int {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/extra_import/mock.go b/mockgen/internal/tests/extra_import/mock.go
index 1c3173c..da611a8 100644
--- a/mockgen/internal/tests/extra_import/mock.go
+++ b/mockgen/internal/tests/extra_import/mock.go
@@ -19,6 +19,7 @@ import (
 type MockFoo struct {
 	ctrl     *gomock.Controller
 	recorder *MockFooMockRecorder
+	isgomock struct{}
 }
 
 // MockFooMockRecorder is the mock recorder for MockFoo.
@@ -38,11 +39,6 @@ func (m *MockFoo) EXPECT() *MockFooMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockFoo) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Bar mocks base method.
 func (m *MockFoo) Bar(arg0 []string, arg1 chan<- Message) {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/generated_identifier_conflict/bugreport_mock.go b/mockgen/internal/tests/generated_identifier_conflict/bugreport_mock.go
index cf871e1..e066b90 100644
--- a/mockgen/internal/tests/generated_identifier_conflict/bugreport_mock.go
+++ b/mockgen/internal/tests/generated_identifier_conflict/bugreport_mock.go
@@ -19,6 +19,7 @@ import (
 type MockExample struct {
 	ctrl     *gomock.Controller
 	recorder *MockExampleMockRecorder
+	isgomock struct{}
 }
 
 // MockExampleMockRecorder is the mock recorder for MockExample.
@@ -38,11 +39,6 @@ func (m *MockExample) EXPECT() *MockExampleMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockExample) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Method mocks base method.
 func (m_2 *MockExample) Method(_m, _mr, m, mr int) {
 	m_2.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/import_embedded_interface/bugreport_mock.go b/mockgen/internal/tests/import_embedded_interface/bugreport_mock.go
index 5564c86..bd89e59 100644
--- a/mockgen/internal/tests/import_embedded_interface/bugreport_mock.go
+++ b/mockgen/internal/tests/import_embedded_interface/bugreport_mock.go
@@ -21,6 +21,7 @@ import (
 type MockSource struct {
 	ctrl     *gomock.Controller
 	recorder *MockSourceMockRecorder
+	isgomock struct{}
 }
 
 // MockSourceMockRecorder is the mock recorder for MockSource.
@@ -40,11 +41,6 @@ func (m *MockSource) EXPECT() *MockSourceMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockSource) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Bar mocks base method.
 func (m *MockSource) Bar() Baz {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/import_embedded_interface/net_mock.go b/mockgen/internal/tests/import_embedded_interface/net_mock.go
index 1f7ba06..0c7da5b 100644
--- a/mockgen/internal/tests/import_embedded_interface/net_mock.go
+++ b/mockgen/internal/tests/import_embedded_interface/net_mock.go
@@ -20,6 +20,7 @@ import (
 type MockNet struct {
 	ctrl     *gomock.Controller
 	recorder *MockNetMockRecorder
+	isgomock struct{}
 }
 
 // MockNetMockRecorder is the mock recorder for MockNet.
@@ -39,11 +40,6 @@ func (m *MockNet) EXPECT() *MockNetMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockNet) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Header mocks base method.
 func (m *MockNet) Header() http.Header {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/import_source/definition/source_mock.go b/mockgen/internal/tests/import_source/definition/source_mock.go
index 318544a..a819a6a 100644
--- a/mockgen/internal/tests/import_source/definition/source_mock.go
+++ b/mockgen/internal/tests/import_source/definition/source_mock.go
@@ -19,6 +19,7 @@ import (
 type MockS struct {
 	ctrl     *gomock.Controller
 	recorder *MockSMockRecorder
+	isgomock struct{}
 }
 
 // MockSMockRecorder is the mock recorder for MockS.
@@ -38,11 +39,6 @@ func (m *MockS) EXPECT() *MockSMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockS) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // F mocks base method.
 func (m *MockS) F(arg0 X) {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/import_source/source_mock.go b/mockgen/internal/tests/import_source/source_mock.go
index 7605f4a..5538ed7 100644
--- a/mockgen/internal/tests/import_source/source_mock.go
+++ b/mockgen/internal/tests/import_source/source_mock.go
@@ -20,6 +20,7 @@ import (
 type MockS struct {
 	ctrl     *gomock.Controller
 	recorder *MockSMockRecorder
+	isgomock struct{}
 }
 
 // MockSMockRecorder is the mock recorder for MockS.
@@ -39,11 +40,6 @@ func (m *MockS) EXPECT() *MockSMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockS) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // F mocks base method.
 func (m *MockS) F(arg0 source.X) {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/internal_pkg/subdir/internal/pkg/source_output/mock.go b/mockgen/internal/tests/internal_pkg/subdir/internal/pkg/source_output/mock.go
index 0f841bf..52adf40 100644
--- a/mockgen/internal/tests/internal_pkg/subdir/internal/pkg/source_output/mock.go
+++ b/mockgen/internal/tests/internal_pkg/subdir/internal/pkg/source_output/mock.go
@@ -20,6 +20,7 @@ import (
 type MockArg struct {
 	ctrl     *gomock.Controller
 	recorder *MockArgMockRecorder
+	isgomock struct{}
 }
 
 // MockArgMockRecorder is the mock recorder for MockArg.
@@ -39,11 +40,6 @@ func (m *MockArg) EXPECT() *MockArgMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockArg) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Foo mocks base method.
 func (m *MockArg) Foo() int {
 	m.ctrl.T.Helper()
@@ -62,6 +58,7 @@ func (mr *MockArgMockRecorder) Foo() *gomock.Call {
 type MockIntf struct {
 	ctrl     *gomock.Controller
 	recorder *MockIntfMockRecorder
+	isgomock struct{}
 }
 
 // MockIntfMockRecorder is the mock recorder for MockIntf.
@@ -81,11 +78,6 @@ func (m *MockIntf) EXPECT() *MockIntfMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockIntf) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // F mocks base method.
 func (m *MockIntf) F() pkg.Arg {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/missing_import/output/source_mock.go b/mockgen/internal/tests/missing_import/output/source_mock.go
index 7f20a99..3f38ad8 100644
--- a/mockgen/internal/tests/missing_import/output/source_mock.go
+++ b/mockgen/internal/tests/missing_import/output/source_mock.go
@@ -20,6 +20,7 @@ import (
 type MockBar struct {
 	ctrl     *gomock.Controller
 	recorder *MockBarMockRecorder
+	isgomock struct{}
 }
 
 // MockBarMockRecorder is the mock recorder for MockBar.
@@ -39,11 +40,6 @@ func (m *MockBar) EXPECT() *MockBarMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockBar) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Baz mocks base method.
 func (m *MockBar) Baz(arg0 source.Foo) {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/mock_in_test_package/mock_test.go b/mockgen/internal/tests/mock_in_test_package/mock_test.go
index 6b187d8..ead45ab 100644
--- a/mockgen/internal/tests/mock_in_test_package/mock_test.go
+++ b/mockgen/internal/tests/mock_in_test_package/mock_test.go
@@ -20,6 +20,7 @@ import (
 type MockFinder struct {
 	ctrl     *gomock.Controller
 	recorder *MockFinderMockRecorder
+	isgomock struct{}
 }
 
 // MockFinderMockRecorder is the mock recorder for MockFinder.
@@ -39,11 +40,6 @@ func (m *MockFinder) EXPECT() *MockFinderMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockFinder) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Add mocks base method.
 func (m *MockFinder) Add(u users.User) {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/mock_name/mocks/post_service.go b/mockgen/internal/tests/mock_name/mocks/post_service.go
index d1dcc6d..d8dc033 100644
--- a/mockgen/internal/tests/mock_name/mocks/post_service.go
+++ b/mockgen/internal/tests/mock_name/mocks/post_service.go
@@ -21,6 +21,7 @@ import (
 type PostServiceMock struct {
 	ctrl     *gomock.Controller
 	recorder *PostServiceMockMockRecorder
+	isgomock struct{}
 }
 
 // PostServiceMockMockRecorder is the mock recorder for PostServiceMock.
@@ -40,11 +41,6 @@ func (m *PostServiceMock) EXPECT() *PostServiceMockMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *PostServiceMock) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Create mocks base method.
 func (m *PostServiceMock) Create(arg0, arg1 string, arg2 *user.User) (*post.Post, error) {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/mock_name/mocks/user_service.go b/mockgen/internal/tests/mock_name/mocks/user_service.go
index 8842eae..6447691 100644
--- a/mockgen/internal/tests/mock_name/mocks/user_service.go
+++ b/mockgen/internal/tests/mock_name/mocks/user_service.go
@@ -20,6 +20,7 @@ import (
 type UserServiceMock struct {
 	ctrl     *gomock.Controller
 	recorder *UserServiceMockMockRecorder
+	isgomock struct{}
 }
 
 // UserServiceMockMockRecorder is the mock recorder for UserServiceMock.
@@ -39,11 +40,6 @@ func (m *UserServiceMock) EXPECT() *UserServiceMockMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *UserServiceMock) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Create mocks base method.
 func (m *UserServiceMock) Create(arg0 string) (*user.User, error) {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/overlapping_methods/mock.go b/mockgen/internal/tests/overlapping_methods/mock.go
index 2cd0751..7f5c44b 100644
--- a/mockgen/internal/tests/overlapping_methods/mock.go
+++ b/mockgen/internal/tests/overlapping_methods/mock.go
@@ -19,6 +19,7 @@ import (
 type MockReadWriteCloser struct {
 	ctrl     *gomock.Controller
 	recorder *MockReadWriteCloserMockRecorder
+	isgomock struct{}
 }
 
 // MockReadWriteCloserMockRecorder is the mock recorder for MockReadWriteCloser.
@@ -38,11 +39,6 @@ func (m *MockReadWriteCloser) EXPECT() *MockReadWriteCloserMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockReadWriteCloser) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Close mocks base method.
 func (m *MockReadWriteCloser) Close() error {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/package_comment/mock.go b/mockgen/internal/tests/package_comment/mock.go
index 8b5a097..f2fb9fb 100644
--- a/mockgen/internal/tests/package_comment/mock.go
+++ b/mockgen/internal/tests/package_comment/mock.go
@@ -16,6 +16,7 @@ import (
 type MockEmpty struct {
 	ctrl     *gomock.Controller
 	recorder *MockEmptyMockRecorder
+	isgomock struct{}
 }
 
 // MockEmptyMockRecorder is the mock recorder for MockEmpty.
@@ -34,8 +35,3 @@ func NewMockEmpty(ctrl *gomock.Controller) *MockEmpty {
 func (m *MockEmpty) EXPECT() *MockEmptyMockRecorder {
 	return m.recorder
 }
-
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockEmpty) ISGOMOCK() struct{} {
-	return struct{}{}
-}
diff --git a/mockgen/internal/tests/panicing_test/mock_test.go b/mockgen/internal/tests/panicing_test/mock_test.go
index 42e5fae..aef67e6 100644
--- a/mockgen/internal/tests/panicing_test/mock_test.go
+++ b/mockgen/internal/tests/panicing_test/mock_test.go
@@ -19,6 +19,7 @@ import (
 type MockFoo struct {
 	ctrl     *gomock.Controller
 	recorder *MockFooMockRecorder
+	isgomock struct{}
 }
 
 // MockFooMockRecorder is the mock recorder for MockFoo.
@@ -38,11 +39,6 @@ func (m *MockFoo) EXPECT() *MockFooMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockFoo) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Bar mocks base method.
 func (m *MockFoo) Bar() string {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/sanitization/mockout/mock.go b/mockgen/internal/tests/sanitization/mockout/mock.go
index 8e130b9..345d2b8 100644
--- a/mockgen/internal/tests/sanitization/mockout/mock.go
+++ b/mockgen/internal/tests/sanitization/mockout/mock.go
@@ -20,6 +20,7 @@ import (
 type MockAnyMock struct {
 	ctrl     *gomock.Controller
 	recorder *MockAnyMockMockRecorder
+	isgomock struct{}
 }
 
 // MockAnyMockMockRecorder is the mock recorder for MockAnyMock.
@@ -39,11 +40,6 @@ func (m *MockAnyMock) EXPECT() *MockAnyMockMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockAnyMock) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Do mocks base method.
 func (m *MockAnyMock) Do(arg0 *any0.Any, arg1 int) {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/self_package/mock.go b/mockgen/internal/tests/self_package/mock.go
index 18494fa..05a5761 100644
--- a/mockgen/internal/tests/self_package/mock.go
+++ b/mockgen/internal/tests/self_package/mock.go
@@ -19,6 +19,7 @@ import (
 type MockMethods struct {
 	ctrl     *gomock.Controller
 	recorder *MockMethodsMockRecorder
+	isgomock struct{}
 }
 
 // MockMethodsMockRecorder is the mock recorder for MockMethods.
@@ -38,11 +39,6 @@ func (m *MockMethods) EXPECT() *MockMethodsMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockMethods) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // getInfo mocks base method.
 func (m *MockMethods) getInfo() Info {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/test_package/mock_test.go b/mockgen/internal/tests/test_package/mock_test.go
index e0a5a0d..ed8ca9b 100644
--- a/mockgen/internal/tests/test_package/mock_test.go
+++ b/mockgen/internal/tests/test_package/mock_test.go
@@ -19,6 +19,7 @@ import (
 type MockFinder struct {
 	ctrl     *gomock.Controller
 	recorder *MockFinderMockRecorder
+	isgomock struct{}
 }
 
 // MockFinderMockRecorder is the mock recorder for MockFinder.
@@ -38,11 +39,6 @@ func (m *MockFinder) EXPECT() *MockFinderMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockFinder) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Add mocks base method.
 func (m *MockFinder) Add(u User) {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/typed_inorder/mock.go b/mockgen/internal/tests/typed_inorder/mock.go
index ff98128..e7a21e3 100644
--- a/mockgen/internal/tests/typed_inorder/mock.go
+++ b/mockgen/internal/tests/typed_inorder/mock.go
@@ -19,6 +19,7 @@ import (
 type MockAnimal struct {
 	ctrl     *gomock.Controller
 	recorder *MockAnimalMockRecorder
+	isgomock struct{}
 }
 
 // MockAnimalMockRecorder is the mock recorder for MockAnimal.
@@ -38,11 +39,6 @@ func (m *MockAnimal) EXPECT() *MockAnimalMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockAnimal) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Feed mocks base method.
 func (m *MockAnimal) Feed(arg0 string) error {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/unexported_method/bugreport_mock.go b/mockgen/internal/tests/unexported_method/bugreport_mock.go
index 8cb2e03..5670756 100644
--- a/mockgen/internal/tests/unexported_method/bugreport_mock.go
+++ b/mockgen/internal/tests/unexported_method/bugreport_mock.go
@@ -19,6 +19,7 @@ import (
 type MockExample struct {
 	ctrl     *gomock.Controller
 	recorder *MockExampleMockRecorder
+	isgomock struct{}
 }
 
 // MockExampleMockRecorder is the mock recorder for MockExample.
@@ -38,11 +39,6 @@ func (m *MockExample) EXPECT() *MockExampleMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockExample) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // someMethod mocks base method.
 func (m *MockExample) someMethod(arg0 string) string {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/vendor_dep/mock.go b/mockgen/internal/tests/vendor_dep/mock.go
index 7ce6fd4..ae663b6 100644
--- a/mockgen/internal/tests/vendor_dep/mock.go
+++ b/mockgen/internal/tests/vendor_dep/mock.go
@@ -20,6 +20,7 @@ import (
 type MockVendorsDep struct {
 	ctrl     *gomock.Controller
 	recorder *MockVendorsDepMockRecorder
+	isgomock struct{}
 }
 
 // MockVendorsDepMockRecorder is the mock recorder for MockVendorsDep.
@@ -39,11 +40,6 @@ func (m *MockVendorsDep) EXPECT() *MockVendorsDepMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockVendorsDep) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Foo mocks base method.
 func (m *MockVendorsDep) Foo() present.Elem {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/vendor_dep/source_mock_package/mock.go b/mockgen/internal/tests/vendor_dep/source_mock_package/mock.go
index b55394a..88461e2 100644
--- a/mockgen/internal/tests/vendor_dep/source_mock_package/mock.go
+++ b/mockgen/internal/tests/vendor_dep/source_mock_package/mock.go
@@ -20,6 +20,7 @@ import (
 type MockVendorsDep struct {
 	ctrl     *gomock.Controller
 	recorder *MockVendorsDepMockRecorder
+	isgomock struct{}
 }
 
 // MockVendorsDepMockRecorder is the mock recorder for MockVendorsDep.
@@ -39,11 +40,6 @@ func (m *MockVendorsDep) EXPECT() *MockVendorsDepMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockVendorsDep) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // Foo mocks base method.
 func (m *MockVendorsDep) Foo() present.Elem {
 	m.ctrl.T.Helper()
diff --git a/mockgen/internal/tests/vendor_pkg/mock.go b/mockgen/internal/tests/vendor_pkg/mock.go
index 10eb886..e32fb0f 100644
--- a/mockgen/internal/tests/vendor_pkg/mock.go
+++ b/mockgen/internal/tests/vendor_pkg/mock.go
@@ -19,6 +19,7 @@ import (
 type MockElem struct {
 	ctrl     *gomock.Controller
 	recorder *MockElemMockRecorder
+	isgomock struct{}
 }
 
 // MockElemMockRecorder is the mock recorder for MockElem.
@@ -38,11 +39,6 @@ func (m *MockElem) EXPECT() *MockElemMockRecorder {
 	return m.recorder
 }
 
-// ISGOMOCK indicates that this struct is a gomock mock.
-func (m *MockElem) ISGOMOCK() struct{} {
-	return struct{}{}
-}
-
 // TemplateName mocks base method.
 func (m *MockElem) TemplateName() string {
 	m.ctrl.T.Helper()
diff --git a/mockgen/mockgen.go b/mockgen/mockgen.go
index 5d57868..6d7634b 100644
--- a/mockgen/mockgen.go
+++ b/mockgen/mockgen.go
@@ -477,6 +477,7 @@ func (g *generator) GenerateMockInterface(intf *model.Interface, outputPackagePa
 	g.in()
 	g.p("ctrl     *gomock.Controller")
 	g.p("recorder *%vMockRecorder%v", mockType, shortTp)
+	g.p("isgomock struct{}")
 	g.out()
 	g.p("}")
 	g.p("")
@@ -507,14 +508,6 @@ func (g *generator) GenerateMockInterface(intf *model.Interface, outputPackagePa
 	g.out()
 	g.p("}")
 
-	// XXX: possible name collision here if someone has ISGOMOCK in their interface.
-	g.p("// ISGOMOCK indicates that this struct is a gomock mock.")
-	g.p("func (m *%v%v) ISGOMOCK() struct{} {", mockType, shortTp)
-	g.in()
-	g.p("return struct{}{}")
-	g.out()
-	g.p("}")
-
 	g.GenerateMockMethods(mockType, intf, outputPackagePath, longTp, shortTp, *typed)
 
 	return nil