diff --git a/code/go/internal/validator/semantic/types.go b/code/go/internal/validator/semantic/types.go
index 088355805..3f7f9decb 100644
--- a/code/go/internal/validator/semantic/types.go
+++ b/code/go/internal/validator/semantic/types.go
@@ -23,6 +23,7 @@ type field struct {
 	Unit       string `yaml:"unit"`
 	MetricType string `yaml:"metric_type"`
 	Dimension  bool   `yaml:"dimension"`
+	External   string `yaml:"external"`
 
 	Fields fields `yaml:"fields"`
 }
diff --git a/code/go/internal/validator/semantic/validate_dimensions.go b/code/go/internal/validator/semantic/validate_dimensions.go
index 7f1250030..6306d3c35 100644
--- a/code/go/internal/validator/semantic/validate_dimensions.go
+++ b/code/go/internal/validator/semantic/validate_dimensions.go
@@ -17,6 +17,11 @@ func ValidateDimensionFields(pkgRoot string) errors.ValidationErrors {
 }
 
 func validateDimensionField(fieldsFile string, f field) errors.ValidationErrors {
+	if f.External != "" {
+		// TODO: External fields can be used as dimensions, but we cannot resolve
+		// them at this point, so accept them as they are by now.
+		return nil
+	}
 	if f.Dimension && !isAllowedDimensionType(f.Type) {
 		return errors.ValidationErrors{fmt.Errorf(`file "%s" is invalid: field "%s" of type %s can't be a dimension, allowed types for dimensions: %s`, fieldsFile, f.Name, f.Type, strings.Join(allowedDimensionTypes, ", "))}
 	}
diff --git a/code/go/internal/validator/semantic/validate_dimensions_test.go b/code/go/internal/validator/semantic/validate_dimensions_test.go
index 8bc349fe9..f0d9e6829 100644
--- a/code/go/internal/validator/semantic/validate_dimensions_test.go
+++ b/code/go/internal/validator/semantic/validate_dimensions_test.go
@@ -69,6 +69,15 @@ func TestValidateDimensionFields(t *testing.T) {
 			},
 			valid: false,
 		},
+		{
+			title: "external field as dimension should be supported",
+			field: field{
+				Name:      "container.id",
+				External:  "ecs",
+				Dimension: true,
+			},
+			valid: true,
+		},
 	}
 
 	for _, c := range cases {
diff --git a/test/packages/time_series/data_stream/example/fields/ecs.yml b/test/packages/time_series/data_stream/example/fields/ecs.yml
new file mode 100644
index 000000000..1706e98b6
--- /dev/null
+++ b/test/packages/time_series/data_stream/example/fields/ecs.yml
@@ -0,0 +1,3 @@
+- name: container.id
+  external: ecs
+  dimension: true
diff --git a/versions/1/changelog.yml b/versions/1/changelog.yml
index 9db113e37..96ff72e03 100644
--- a/versions/1/changelog.yml
+++ b/versions/1/changelog.yml
@@ -13,6 +13,9 @@
   - description: Add email, time_zone and url config types.
     type: enhancement
     link: https://github.com/elastic/package-spec/pull/241
+  - description: Add support for dimension fields from external sources.
+    type: enhancement
+    link: https://github.com/elastic/package-spec/pull/248
 - version: 1.2.0
   changes:
   - description: Add tag support for elastic export