diff --git a/internal/resources/api_server_certificate.go b/internal/resources/api_server_certificate.go
index fe2e715..436cdf9 100644
--- a/internal/resources/api_server_certificate.go
+++ b/internal/resources/api_server_certificate.go
@@ -136,9 +136,9 @@ func (r *APIServerCertificate) mutate(ctx context.Context, tenantControlPlane *k
 
 			commonNames := config.InitConfiguration.APIServer.CertSANs
 
-			if tenantControlPlane.Spec.ControlPlane.Ingress != nil {
-				address, _ := utilities.GetControlPlaneAddressAndPortFromHostname(tenantControlPlane.Spec.ControlPlane.Ingress.Hostname, 6443)
-				commonNames = append(commonNames, address)
+			addr, _, aErr := tenantControlPlane.AssignedControlPlaneAddress()
+			if aErr == nil {
+				commonNames = append(commonNames, addr)
 			}
 
 			dnsNamesMatches, dnsErr := crypto.CheckCertificateNamesAndIPs(r.resource.Data[kubeadmconstants.APIServerCertName], commonNames)