diff --git a/pkg/api/v1/atlasproject_types.go b/pkg/api/v1/atlasproject_types.go
index 2841d81b73..65d811299b 100644
--- a/pkg/api/v1/atlasproject_types.go
+++ b/pkg/api/v1/atlasproject_types.go
@@ -157,7 +157,11 @@ func (p *AtlasProject) UpdateStatus(conditions []status.Condition, options ...st
 
 func (p *AtlasProject) X509SecretObjectKey() *client.ObjectKey {
 	if p.Spec.X509CertRef != nil {
-		key := kube.ObjectKey(p.Namespace, p.Spec.X509CertRef.Name)
+		namespace := p.Spec.X509CertRef.Namespace
+		if namespace == "" {
+			namespace = p.Namespace
+		}
+		key := kube.ObjectKey(namespace, p.Spec.X509CertRef.Name)
 		return &key
 	}
 	return nil