diff --git a/pkg/apis/core/types.go b/pkg/apis/core/types.go
index b6b570b06e4..4a80b4dfa02 100644
--- a/pkg/apis/core/types.go
+++ b/pkg/apis/core/types.go
@@ -2338,13 +2338,13 @@ type PodAffinityTerm struct {
 	LabelSelector *metav1.LabelSelector
 	// namespaces specifies which namespaces the labelSelector applies to (matches against);
 	// null or empty list means "this pod's namespace"
+	// +optional
 	Namespaces []string
 	// This pod should be co-located (affinity) or not co-located (anti-affinity) with the pods matching
 	// the labelSelector in the specified namespaces, where co-located is defined as running on a node
 	// whose value of the label with key topologyKey matches that of any node on which any of the
 	// selected pods is running.
 	// Empty topologyKey is not allowed.
-	// +optional
 	TopologyKey string
 }
 
diff --git a/staging/src/k8s.io/api/core/v1/generated.proto b/staging/src/k8s.io/api/core/v1/generated.proto
index de2c1e690e8..d89a7015f6e 100644
--- a/staging/src/k8s.io/api/core/v1/generated.proto
+++ b/staging/src/k8s.io/api/core/v1/generated.proto
@@ -2619,6 +2619,7 @@ message PodAffinityTerm {
 
   // namespaces specifies which namespaces the labelSelector applies to (matches against);
   // null or empty list means "this pod's namespace"
+  // +optional
   repeated string namespaces = 2;
 
   // This pod should be co-located (affinity) or not co-located (anti-affinity) with the pods matching
diff --git a/staging/src/k8s.io/api/core/v1/types.go b/staging/src/k8s.io/api/core/v1/types.go
index 728cbd5a62b..e859c0ae690 100644
--- a/staging/src/k8s.io/api/core/v1/types.go
+++ b/staging/src/k8s.io/api/core/v1/types.go
@@ -2585,6 +2585,7 @@ type PodAffinityTerm struct {
 	LabelSelector *metav1.LabelSelector `json:"labelSelector,omitempty" protobuf:"bytes,1,opt,name=labelSelector"`
 	// namespaces specifies which namespaces the labelSelector applies to (matches against);
 	// null or empty list means "this pod's namespace"
+	// +optional
 	Namespaces []string `json:"namespaces,omitempty" protobuf:"bytes,2,rep,name=namespaces"`
 	// This pod should be co-located (affinity) or not co-located (anti-affinity) with the pods matching
 	// the labelSelector in the specified namespaces, where co-located is defined as running on a node