diff --git a/staging/src/k8s.io/apimachinery/pkg/util/validation/validation.go b/staging/src/k8s.io/apimachinery/pkg/util/validation/validation.go
index b6be7af1b16..bc4521c392b 100644
--- a/staging/src/k8s.io/apimachinery/pkg/util/validation/validation.go
+++ b/staging/src/k8s.io/apimachinery/pkg/util/validation/validation.go
@@ -235,7 +235,7 @@ func IsDNS1123SubdomainWithUnderscore(value string) []string {
 		errs = append(errs, MaxLenError(DNS1123SubdomainMaxLength))
 	}
 	if !dns1123SubdomainRegexpWithUnderscore.MatchString(value) {
-		errs = append(errs, RegexError(dns1123SubdomainErrorMsgFG, dns1123SubdomainFmt, "example.com"))
+		errs = append(errs, RegexError(dns1123SubdomainErrorMsgFG, dns1123SubdomainFmtWithUnderscore, "example.com"))
 	}
 	return errs
 }
diff --git a/staging/src/k8s.io/apimachinery/pkg/util/validation/validation_test.go b/staging/src/k8s.io/apimachinery/pkg/util/validation/validation_test.go
index 848fb60edb9..acfe2cb7687 100644
--- a/staging/src/k8s.io/apimachinery/pkg/util/validation/validation_test.go
+++ b/staging/src/k8s.io/apimachinery/pkg/util/validation/validation_test.go
@@ -17,6 +17,7 @@ limitations under the License.
 package validation
 
 import (
+	"reflect"
 	"strings"
 	"testing"
 
@@ -635,3 +636,86 @@ func TestIsRelaxedEnvVarName(t *testing.T) {
 		}
 	}
 }
+
+func TestIsDNS1123SubdomainWithUnderscore(t *testing.T) {
+	tests := []struct {
+		name     string
+		value    string
+		expected []string
+	}{
+		{
+			name:     "valid subdomain",
+			value:    "example.com",
+			expected: nil,
+		},
+		{
+			name:     "valid subdomain with underscore",
+			value:    "_example.com",
+			expected: nil,
+		},
+		{
+			name:     "valid subdomain with multiple segments",
+			value:    "sub._example.com",
+			expected: nil,
+		},
+		{
+			name:     "valid subdomain with hyphen",
+			value:    "sub-domain.example.com",
+			expected: nil,
+		},
+		{
+			name:     "valid subdomain with underscore in middle",
+			value:    "sub_domain.example.com",
+			expected: nil,
+		},
+		{
+			name:     "empty string",
+			value:    "",
+			expected: []string{RegexError(dns1123SubdomainErrorMsgFG, dns1123SubdomainFmtWithUnderscore, "example.com")},
+		},
+		{
+			name:     "invalid uppercase characters",
+			value:    "Example.com",
+			expected: []string{RegexError(dns1123SubdomainErrorMsgFG, dns1123SubdomainFmtWithUnderscore, "example.com")},
+		},
+		{
+			name:     "invalid starting character",
+			value:    "-example.com",
+			expected: []string{RegexError(dns1123SubdomainErrorMsgFG, dns1123SubdomainFmtWithUnderscore, "example.com")},
+		},
+		{
+			name:     "invalid ending character",
+			value:    "example.com-",
+			expected: []string{RegexError(dns1123SubdomainErrorMsgFG, dns1123SubdomainFmtWithUnderscore, "example.com")},
+		},
+		{
+			name:     "invalid characters",
+			value:    "example@.com",
+			expected: []string{RegexError(dns1123SubdomainErrorMsgFG, dns1123SubdomainFmtWithUnderscore, "example.com")},
+		},
+		{
+			name:     "too long subdomain",
+			value:    "a." + string(make([]byte, 251)) + ".com",
+			expected: []string{MaxLenError(DNS1123SubdomainMaxLength), RegexError(dns1123SubdomainErrorMsgFG, dns1123SubdomainFmtWithUnderscore, "example.com")},
+		},
+		{
+			name:     "multiple dots",
+			value:    "example..com",
+			expected: []string{RegexError(dns1123SubdomainErrorMsgFG, dns1123SubdomainFmtWithUnderscore, "example.com")},
+		},
+		{
+			name:     "underscore only",
+			value:    "_",
+			expected: []string{RegexError(dns1123SubdomainErrorMsgFG, dns1123SubdomainFmtWithUnderscore, "example.com")},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := IsDNS1123SubdomainWithUnderscore(tt.value)
+			if !reflect.DeepEqual(result, tt.expected) {
+				t.Errorf("IsDNS1123SubdomainWithUnderscore(%q) = %v; want %v", tt.value, result, tt.expected)
+			}
+		})
+	}
+}