diff --git a/pkg/webhook/playground_webhook.go b/pkg/webhook/playground_webhook.go
index 96272950..9e32a703 100644
--- a/pkg/webhook/playground_webhook.go
+++ b/pkg/webhook/playground_webhook.go
@@ -103,6 +103,9 @@ func (w *PlaygroundWebhook) generateValidate(obj runtime.Object) field.ErrorList
 	if playground.Spec.ModelClaim == nil && playground.Spec.ModelClaims == nil {
 		allErrs = append(allErrs, field.Forbidden(specPath, "modelClaim and modelClaims couldn't be both nil"))
 	}
+	if playground.Spec.ModelClaim != nil && playground.Spec.ModelClaims != nil {
+		allErrs = append(allErrs, field.Forbidden(specPath, "modelClaim and modelClaims couldn't be both not nil"))
+	}
 	if playground.Spec.ModelClaims != nil {
 		mainModelCount := 0
 
diff --git a/test/integration/webhook/playground_test.go b/test/integration/webhook/playground_test.go
index f2f8708d..946bdd16 100644
--- a/test/integration/webhook/playground_test.go
+++ b/test/integration/webhook/playground_test.go
@@ -87,6 +87,13 @@ var _ = ginkgo.Describe("Playground default and validation", func() {
 			},
 			failed: true,
 		}),
+		ginkgo.Entry("both model claim and claims be set", &testValidatingCase{
+			playground: func() *inferenceapi.Playground {
+				return wrapper.MakePlayground("playground", ns.Name).Replicas(1).ModelClaim("llama3-8b").
+					ModelClaims([]string{"llama3-405b", "llama3-2b"}, []string{"main", "draft", "draft"}).Obj()
+			},
+			failed: true,
+		}),
 		ginkgo.Entry("any kind of backendRuntime should be supported", &testValidatingCase{
 			playground: func() *inferenceapi.Playground {
 				return wrapper.MakePlayground("playground", ns.Name).Replicas(1).ModelClaim("llama3-8b").BackendRuntime(string("unknown")).Obj()
@@ -141,7 +148,7 @@ var _ = ginkgo.Describe("Playground default and validation", func() {
 		playground     func() *inferenceapi.Playground
 		wantPlayground func() *inferenceapi.Playground
 	}
-	ginkgo.DescribeTable("test validating",
+	ginkgo.DescribeTable("test Defaulting",
 		func(tc *testDefaultingCase) {
 			playground := tc.playground()
 			gomega.Expect(k8sClient.Create(ctx, playground)).To(gomega.Succeed())