diff --git a/types.go b/types.go
index 78817b7..4665f23 100644
--- a/types.go
+++ b/types.go
@@ -104,21 +104,27 @@ func Register(v interface{}, args ...string) {
 }
 
 // TypeURL returns the type url for a registered type.
-func TypeURL(v interface{}) (string, error) {
+func TypeURL(v interface{}) (u string, err error) {
+	u, _, err = typeURL(v)
+	return
+}
+
+// typeURL returns the type url and whether it was registered for json
+func typeURL(v interface{}) (string, bool, error) {
 	mu.RLock()
 	u, ok := registry[tryDereference(v)]
 	mu.RUnlock()
 	if !ok {
 		switch t := v.(type) {
 		case proto.Message:
-			return string(t.ProtoReflect().Descriptor().FullName()), nil
+			return string(t.ProtoReflect().Descriptor().FullName()), ok, nil
 		case gogoproto.Message:
-			return gogoproto.MessageName(t), nil
+			return gogoproto.MessageName(t), ok, nil
 		default:
-			return "", fmt.Errorf("type %s: %w", reflect.TypeOf(v), ErrNotFound)
+			return "", ok, fmt.Errorf("type %s: %w", reflect.TypeOf(v), ErrNotFound)
 		}
 	}
-	return u, nil
+	return u, ok, nil
 }
 
 // Is returns true if the type of the Any is the same as v.
@@ -140,36 +146,35 @@ func Is(any Any, v interface{}) bool {
 // returned verbatim. If it is of type proto.Message, it will be marshaled as a
 // protocol buffer. Otherwise, the object will be marshaled to json.
 func MarshalAny(v interface{}) (Any, error) {
-	var marshal func(v interface{}) ([]byte, error)
-	switch t := v.(type) {
-	case Any:
-		// avoid reserializing the type if we have an any.
+	if t, ok := v.(Any); ok {
 		return t, nil
-	case proto.Message:
-		marshal = func(v interface{}) ([]byte, error) {
-			return proto.Marshal(t)
-		}
-	case gogoproto.Message:
-		marshal = func(v interface{}) ([]byte, error) {
-			return gogoproto.Marshal(t)
-		}
-	default:
-		marshal = json.Marshal
 	}
 
-	url, err := TypeURL(v)
+	url, isJSON, err := typeURL(v)
 	if err != nil {
 		return nil, err
 	}
-
-	data, err := marshal(v)
+	a := anyType{
+		typeURL: url,
+	}
+	if !isJSON {
+		switch t := v.(type) {
+		case proto.Message:
+			a.value, err = proto.Marshal(t)
+		case gogoproto.Message:
+			a.value, err = gogoproto.Marshal(t)
+		default:
+			isJSON = true
+		}
+	}
+	if isJSON {
+		a.value, err = json.Marshal(v)
+	}
 	if err != nil {
 		return nil, err
 	}
-	return &anyType{
-		typeURL: url,
-		value:   data,
-	}, nil
+
+	return &a, nil
 }
 
 // UnmarshalAny unmarshals the any type into a concrete type.
diff --git a/types_test.go b/types_test.go
index f6c001a..17a5d49 100644
--- a/types_test.go
+++ b/types_test.go
@@ -232,3 +232,29 @@ func TestProtoFallback(t *testing.T) {
 		t.Fatalf("expected %+v but got %+v", expected, ts.AsTime())
 	}
 }
+
+func TestManualProtoRegistration(t *testing.T) {
+	ts := &timestamppb.Timestamp{}
+	defer func() {
+		mu.Lock()
+		delete(registry, tryDereference(ts))
+		mu.Unlock()
+	}()
+	Register(ts, t.Name())
+
+	expected := time.Now()
+	a, err := MarshalAny(timestamppb.New(expected))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	i, err := UnmarshalAny(a)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	actual := i.(*timestamppb.Timestamp).AsTime()
+	if !actual.Equal(expected) {
+		t.Fatalf("unexpected time %s, expected %s", actual, expected)
+	}
+}