diff --git a/pkg/endpoints/openapi/openapi.go b/pkg/endpoints/openapi/openapi.go
index e512f29b3..e3bd028bb 100644
--- a/pkg/endpoints/openapi/openapi.go
+++ b/pkg/endpoints/openapi/openapi.go
@@ -108,6 +108,18 @@ func (s groupVersionKinds) Less(i, j int) bool {
 	return s[i].Group < s[j].Group
 }
 
+func (s groupVersionKinds) JSON() []interface{} {
+	j := []interface{}{}
+	for _, gvk := range s {
+		j = append(j, map[string]interface{}{
+			"group":   gvk.Group,
+			"version": gvk.Version,
+			"kind":    gvk.Kind,
+		})
+	}
+	return j
+}
+
 // DefinitionNamer is the type to customize OpenAPI definition name.
 type DefinitionNamer struct {
 	typeGroupVersionKinds map[string]groupVersionKinds
@@ -172,7 +184,7 @@ func NewDefinitionNamer(schemes ...*runtime.Scheme) *DefinitionNamer {
 func (d *DefinitionNamer) GetDefinitionName(name string) (string, spec.Extensions) {
 	if groupVersionKinds, ok := d.typeGroupVersionKinds[name]; ok {
 		return friendlyName(name), spec.Extensions{
-			extensionGVK: []v1.GroupVersionKind(groupVersionKinds),
+			extensionGVK: groupVersionKinds.JSON(),
 		}
 	}
 	return friendlyName(name), nil
diff --git a/pkg/endpoints/openapi/openapi_test.go b/pkg/endpoints/openapi/openapi_test.go
index fb188fed0..0ebfedeae 100644
--- a/pkg/endpoints/openapi/openapi_test.go
+++ b/pkg/endpoints/openapi/openapi_test.go
@@ -23,7 +23,6 @@ import (
 
 	"github.com/go-openapi/spec"
 
-	"k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	openapitesting "k8s.io/apiserver/pkg/endpoints/openapi/testing"
 )
@@ -58,13 +57,13 @@ func TestGetDefinitionName(t *testing.T) {
 	namer := NewDefinitionNamer(s)
 	n, e := namer.GetDefinitionName(typePkgName)
 	assertEqual(t, typeFriendlyName, n)
-	assertEqual(t, e["x-kubernetes-group-version-kind"], []v1.GroupVersionKind{
-		{
-			Group:   "test",
-			Version: "v1",
-			Kind:    "TestType",
+	assertEqual(t, []interface{}{
+		map[string]interface{}{
+			"group":   "test",
+			"version": "v1",
+			"kind":    "TestType",
 		},
-	})
+	}, e["x-kubernetes-group-version-kind"])
 	n, e2 := namer.GetDefinitionName("test.com/another.Type")
 	assertEqual(t, "com.test.another.Type", n)
 	assertEqual(t, e2, spec.Extensions(nil))
diff --git a/pkg/server/genericapiserver_test.go b/pkg/server/genericapiserver_test.go
index df6b0203c..cd9e57bc2 100644
--- a/pkg/server/genericapiserver_test.go
+++ b/pkg/server/genericapiserver_test.go
@@ -89,18 +89,18 @@ func buildTestOpenAPIDefinition() kubeopenapi.OpenAPIDefinition {
 			},
 			VendorExtensible: openapi.VendorExtensible{
 				Extensions: openapi.Extensions{
-					"x-kubernetes-group-version-kind": []map[string]string{
-						{
+					"x-kubernetes-group-version-kind": []interface{}{
+						map[string]interface{}{
 							"group":   "",
 							"version": "v1",
 							"kind":    "Getter",
 						},
-						{
+						map[string]interface{}{
 							"group":   "batch",
 							"version": "v1",
 							"kind":    "Getter",
 						},
-						{
+						map[string]interface{}{
 							"group":   "extensions",
 							"version": "v1",
 							"kind":    "Getter",
diff --git a/pkg/util/openapi/proto_test.go b/pkg/util/openapi/proto_test.go
index d4ee737ca..4fbd63f18 100644
--- a/pkg/util/openapi/proto_test.go
+++ b/pkg/util/openapi/proto_test.go
@@ -44,8 +44,8 @@ func TestOpenAPIDefinitionsToProtoModels(t *testing.T) {
 					},
 					VendorExtensible: spec.VendorExtensible{
 						Extensions: spec.Extensions{
-							"x-kubernetes-group-version-kind": []map[string]string{
-								{
+							"x-kubernetes-group-version-kind": []interface{}{
+								map[string]interface{}{
 									"group":   "testgroup.k8s.io",
 									"version": "v1",
 									"kind":    "Foo",