diff --git a/api/openapi-spec/swagger.json b/api/openapi-spec/swagger.json
index fd03f68193a..8debdfe453c 100644
--- a/api/openapi-spec/swagger.json
+++ b/api/openapi-spec/swagger.json
@@ -2826,8 +2826,7 @@
       },
       "required": [
         "selector",
-        "template",
-        "serviceName"
+        "template"
       ],
       "type": "object"
     },
diff --git a/api/openapi-spec/v3/apis__apps__v1_openapi.json b/api/openapi-spec/v3/apis__apps__v1_openapi.json
index 4225a147433..3d088868bcd 100644
--- a/api/openapi-spec/v3/apis__apps__v1_openapi.json
+++ b/api/openapi-spec/v3/apis__apps__v1_openapi.json
@@ -1171,8 +1171,7 @@
         },
         "required": [
           "selector",
-          "template",
-          "serviceName"
+          "template"
         ],
         "type": "object"
       },
diff --git a/pkg/apis/apps/types.go b/pkg/apis/apps/types.go
index 8d228de8e4b..a3b7786d462 100644
--- a/pkg/apis/apps/types.go
+++ b/pkg/apis/apps/types.go
@@ -198,6 +198,7 @@ type StatefulSetSpec struct {
 	// the network identity of the set. Pods get DNS/hostnames that follow the
 	// pattern: pod-specific-string.serviceName.default.svc.cluster.local
 	// where "pod-specific-string" is managed by the StatefulSet controller.
+	// +optional
 	ServiceName string
 
 	// PodManagementPolicy controls how pods are created during initial scale up,
diff --git a/pkg/apis/apps/validation/validation.go b/pkg/apis/apps/validation/validation.go
index 6640735dd8c..cff536d9ecf 100644
--- a/pkg/apis/apps/validation/validation.go
+++ b/pkg/apis/apps/validation/validation.go
@@ -34,6 +34,12 @@ import (
 	apivalidation "k8s.io/kubernetes/pkg/apis/core/validation"
 )
 
+// StatefulSetValidationOptions is a struct that can be passed to ValidateStatefulSetSpec to record the validate options
+type StatefulSetValidationOptions struct {
+	// Allow invalid DNS1123 ServiceName
+	AllowInvalidServiceName bool
+}
+
 // ValidateStatefulSetName can be used to check whether the given StatefulSet name is valid.
 // Prefix indicates this name will be used as part of generation, in which case
 // trailing dashes are allowed.
@@ -89,7 +95,7 @@ func ValidatePersistentVolumeClaimRetentionPolicy(policy *apps.StatefulSetPersis
 }
 
 // ValidateStatefulSetSpec tests if required fields in the StatefulSet spec are set.
-func ValidateStatefulSetSpec(spec *apps.StatefulSetSpec, fldPath *field.Path, opts apivalidation.PodValidationOptions) field.ErrorList {
+func ValidateStatefulSetSpec(spec *apps.StatefulSetSpec, fldPath *field.Path, opts apivalidation.PodValidationOptions, setOpts StatefulSetValidationOptions) field.ErrorList {
 	allErrs := field.ErrorList{}
 
 	switch spec.PodManagementPolicy {
@@ -134,6 +140,10 @@ func ValidateStatefulSetSpec(spec *apps.StatefulSetSpec, fldPath *field.Path, op
 		allErrs = append(allErrs, apivalidation.ValidateNonnegativeField(int64(replicaStartOrdinal), fldPath.Child("ordinals.start"))...)
 	}
 
+	if !setOpts.AllowInvalidServiceName && len(spec.ServiceName) > 0 {
+		allErrs = append(allErrs, apivalidation.ValidateDNS1123Label(spec.ServiceName, fldPath.Child("serviceName"))...)
+	}
+
 	if spec.Selector == nil {
 		allErrs = append(allErrs, field.Required(fldPath.Child("selector"), ""))
 	} else {
@@ -164,7 +174,10 @@ func ValidateStatefulSetSpec(spec *apps.StatefulSetSpec, fldPath *field.Path, op
 // ValidateStatefulSet validates a StatefulSet.
 func ValidateStatefulSet(statefulSet *apps.StatefulSet, opts apivalidation.PodValidationOptions) field.ErrorList {
 	allErrs := apivalidation.ValidateObjectMeta(&statefulSet.ObjectMeta, true, ValidateStatefulSetName, field.NewPath("metadata"))
-	allErrs = append(allErrs, ValidateStatefulSetSpec(&statefulSet.Spec, field.NewPath("spec"), opts)...)
+	setOpts := StatefulSetValidationOptions{
+		AllowInvalidServiceName: false, // require valid serviceNames in new StatefulSets
+	}
+	allErrs = append(allErrs, ValidateStatefulSetSpec(&statefulSet.Spec, field.NewPath("spec"), opts, setOpts)...)
 	return allErrs
 }
 
@@ -177,7 +190,10 @@ func ValidateStatefulSetUpdate(statefulSet, oldStatefulSet *apps.StatefulSet, op
 	// thing to do it delete such an instance, but if there is a finalizer, it
 	// would need to pass update validation.  Name can't change anyway.
 	allErrs := apivalidation.ValidateObjectMetaUpdate(&statefulSet.ObjectMeta, &oldStatefulSet.ObjectMeta, field.NewPath("metadata"))
-	allErrs = append(allErrs, ValidateStatefulSetSpec(&statefulSet.Spec, field.NewPath("spec"), opts)...)
+	setOpts := StatefulSetValidationOptions{
+		AllowInvalidServiceName: true, // serviceName is immutable, tolerate existing invalid names on update
+	}
+	allErrs = append(allErrs, ValidateStatefulSetSpec(&statefulSet.Spec, field.NewPath("spec"), opts, setOpts)...)
 
 	// statefulset updates aren't super common and general updates are likely to be touching spec, so we'll do this
 	// deep copy right away.  This avoids mutating our inputs
diff --git a/pkg/apis/apps/validation/validation_test.go b/pkg/apis/apps/validation/validation_test.go
index 96811ca57c5..42d4035f01f 100644
--- a/pkg/apis/apps/validation/validation_test.go
+++ b/pkg/apis/apps/validation/validation_test.go
@@ -195,6 +195,12 @@ func tweakPVCScalePolicy(t apps.PersistentVolumeClaimRetentionPolicyType) pvcPol
 	}
 }
 
+func tweakServiceName(name string) statefulSetTweak {
+	return func(ss *apps.StatefulSet) {
+		ss.Spec.ServiceName = name
+	}
+}
+
 func TestValidateStatefulSet(t *testing.T) {
 	validLabels := map[string]string{"a": "b"}
 	validPodTemplate := api.PodTemplate{
@@ -520,6 +526,14 @@ func TestValidateStatefulSet(t *testing.T) {
 		errs: field.ErrorList{
 			field.Invalid(field.NewPath("spec", "ordinals.start"), nil, ""),
 		},
+	}, {
+		name: "invalid service name",
+		set: mkStatefulSet(&validPodTemplate,
+			tweakServiceName("Invalid.Name"),
+		),
+		errs: field.ErrorList{
+			field.Invalid(field.NewPath("spec", "serviceName"), "Invalid.Name", ""),
+		},
 	},
 	}
 
@@ -595,7 +609,7 @@ func TestValidateStatefulSetMinReadySeconds(t *testing.T) {
 	for tcName, tc := range testCases {
 		t.Run(tcName, func(t *testing.T) {
 			errs := ValidateStatefulSetSpec(tc.ss, field.NewPath("spec", "minReadySeconds"),
-				corevalidation.PodValidationOptions{})
+				corevalidation.PodValidationOptions{}, StatefulSetValidationOptions{})
 			if tc.expectErr && len(errs) == 0 {
 				t.Errorf("Unexpected success")
 			}
@@ -864,6 +878,10 @@ func TestValidateStatefulSetUpdate(t *testing.T) {
 		name:   "update existing instance with .spec.ordinals.start",
 		old:    mkStatefulSet(&validPodTemplate),
 		update: mkStatefulSet(&validPodTemplate, tweakOrdinalsStart(3)),
+	}, {
+		name:   "update with invalid .spec.serviceName",
+		old:    mkStatefulSet(&validPodTemplate, tweakServiceName("Invalid.Name")),
+		update: mkStatefulSet(&validPodTemplate, tweakServiceName("Invalid.Name"), tweakReplicas(3)),
 	},
 	}
 
diff --git a/pkg/generated/openapi/zz_generated.openapi.go b/pkg/generated/openapi/zz_generated.openapi.go
index 95c23c7b167..c86d97600af 100644
--- a/pkg/generated/openapi/zz_generated.openapi.go
+++ b/pkg/generated/openapi/zz_generated.openapi.go
@@ -8251,7 +8251,7 @@ func schema_k8sio_api_apps_v1_StatefulSetSpec(ref common.ReferenceCallback) comm
 						},
 					},
 				},
-				Required: []string{"selector", "template", "serviceName"},
+				Required: []string{"selector", "template"},
 			},
 		},
 		Dependencies: []string{
@@ -9403,7 +9403,7 @@ func schema_k8sio_api_apps_v1beta1_StatefulSetSpec(ref common.ReferenceCallback)
 						},
 					},
 				},
-				Required: []string{"template", "serviceName"},
+				Required: []string{"template"},
 			},
 		},
 		Dependencies: []string{
@@ -11116,7 +11116,7 @@ func schema_k8sio_api_apps_v1beta2_StatefulSetSpec(ref common.ReferenceCallback)
 						},
 					},
 				},
-				Required: []string{"selector", "template", "serviceName"},
+				Required: []string{"selector", "template"},
 			},
 		},
 		Dependencies: []string{
diff --git a/staging/src/k8s.io/api/apps/v1/generated.proto b/staging/src/k8s.io/api/apps/v1/generated.proto
index 453035ca2e0..ac57a15d3e3 100644
--- a/staging/src/k8s.io/api/apps/v1/generated.proto
+++ b/staging/src/k8s.io/api/apps/v1/generated.proto
@@ -716,6 +716,7 @@ message StatefulSetSpec {
   // the network identity of the set. Pods get DNS/hostnames that follow the
   // pattern: pod-specific-string.serviceName.default.svc.cluster.local
   // where "pod-specific-string" is managed by the StatefulSet controller.
+  // +optional
   optional string serviceName = 5;
 
   // podManagementPolicy controls how pods are created during initial scale up,
diff --git a/staging/src/k8s.io/api/apps/v1/types.go b/staging/src/k8s.io/api/apps/v1/types.go
index 0f4102907ca..7368e8ebb47 100644
--- a/staging/src/k8s.io/api/apps/v1/types.go
+++ b/staging/src/k8s.io/api/apps/v1/types.go
@@ -220,6 +220,7 @@ type StatefulSetSpec struct {
 	// the network identity of the set. Pods get DNS/hostnames that follow the
 	// pattern: pod-specific-string.serviceName.default.svc.cluster.local
 	// where "pod-specific-string" is managed by the StatefulSet controller.
+	// +optional
 	ServiceName string `json:"serviceName" protobuf:"bytes,5,opt,name=serviceName"`
 
 	// podManagementPolicy controls how pods are created during initial scale up,
diff --git a/staging/src/k8s.io/api/apps/v1beta1/generated.proto b/staging/src/k8s.io/api/apps/v1beta1/generated.proto
index 24abd5b8ba4..74b3ce54999 100644
--- a/staging/src/k8s.io/api/apps/v1beta1/generated.proto
+++ b/staging/src/k8s.io/api/apps/v1beta1/generated.proto
@@ -462,6 +462,7 @@ message StatefulSetSpec {
   // the network identity of the set. Pods get DNS/hostnames that follow the
   // pattern: pod-specific-string.serviceName.default.svc.cluster.local
   // where "pod-specific-string" is managed by the StatefulSet controller.
+  // +optional
   optional string serviceName = 5;
 
   // podManagementPolicy controls how pods are created during initial scale up,
diff --git a/staging/src/k8s.io/api/apps/v1beta1/types.go b/staging/src/k8s.io/api/apps/v1beta1/types.go
index 85710264fe3..b97a050bfde 100644
--- a/staging/src/k8s.io/api/apps/v1beta1/types.go
+++ b/staging/src/k8s.io/api/apps/v1beta1/types.go
@@ -259,6 +259,7 @@ type StatefulSetSpec struct {
 	// the network identity of the set. Pods get DNS/hostnames that follow the
 	// pattern: pod-specific-string.serviceName.default.svc.cluster.local
 	// where "pod-specific-string" is managed by the StatefulSet controller.
+	// +optional
 	ServiceName string `json:"serviceName" protobuf:"bytes,5,opt,name=serviceName"`
 
 	// podManagementPolicy controls how pods are created during initial scale up,
diff --git a/staging/src/k8s.io/api/apps/v1beta2/generated.proto b/staging/src/k8s.io/api/apps/v1beta2/generated.proto
index 735eed7106e..b0d4e3f0894 100644
--- a/staging/src/k8s.io/api/apps/v1beta2/generated.proto
+++ b/staging/src/k8s.io/api/apps/v1beta2/generated.proto
@@ -761,6 +761,7 @@ message StatefulSetSpec {
   // the network identity of the set. Pods get DNS/hostnames that follow the
   // pattern: pod-specific-string.serviceName.default.svc.cluster.local
   // where "pod-specific-string" is managed by the StatefulSet controller.
+  // +optional
   optional string serviceName = 5;
 
   // podManagementPolicy controls how pods are created during initial scale up,
diff --git a/staging/src/k8s.io/api/apps/v1beta2/types.go b/staging/src/k8s.io/api/apps/v1beta2/types.go
index cc7d6582f50..2d88bfba534 100644
--- a/staging/src/k8s.io/api/apps/v1beta2/types.go
+++ b/staging/src/k8s.io/api/apps/v1beta2/types.go
@@ -269,6 +269,7 @@ type StatefulSetSpec struct {
 	// the network identity of the set. Pods get DNS/hostnames that follow the
 	// pattern: pod-specific-string.serviceName.default.svc.cluster.local
 	// where "pod-specific-string" is managed by the StatefulSet controller.
+	// +optional
 	ServiceName string `json:"serviceName" protobuf:"bytes,5,opt,name=serviceName"`
 
 	// podManagementPolicy controls how pods are created during initial scale up,
diff --git a/test/integration/statefulset/statefulset_test.go b/test/integration/statefulset/statefulset_test.go
index a770e798180..a87bc0eae8b 100644
--- a/test/integration/statefulset/statefulset_test.go
+++ b/test/integration/statefulset/statefulset_test.go
@@ -768,3 +768,35 @@ func TestStatefulSetStartOrdinal(t *testing.T) {
 		})
 	}
 }
+func TestStatefulSetPodSubdomain(t *testing.T) {
+	tCtx, closeFn, rm, informers, c := scSetup(t)
+	defer closeFn()
+	ns := framework.CreateNamespaceOrDie(c, "test-pod-subdomain", t)
+	defer framework.DeleteNamespaceOrDie(c, ns, t)
+	cancel := runControllerAndInformers(tCtx, rm, informers)
+	defer cancel()
+
+	// create a headless service
+	serviceName := "test-service"
+	service := newHeadlessService(ns.Name)
+	service.Name = serviceName
+	createHeadlessService(t, c, service)
+
+	// create StatefulSet with the service name
+	sts := newSTS("sts", ns.Name, 3)
+	sts.Spec.ServiceName = serviceName
+	stss, _ := createSTSsPods(t, c, []*appsv1.StatefulSet{sts}, []*v1.Pod{})
+	sts = stss[0]
+	waitSTSStable(t, c, sts)
+
+	// get pods and verify subdomain
+	labelMap := labelMap()
+	podClient := c.CoreV1().Pods(ns.Name)
+	pods := getPods(t, podClient, labelMap)
+
+	for _, pod := range pods.Items {
+		if pod.Spec.Subdomain != serviceName {
+			t.Errorf("Pod %s has incorrect subdomain: got %s, want %s", pod.Name, pod.Spec.Subdomain, serviceName)
+		}
+	}
+}