diff --git a/lib/mixins/template-stamp.html b/lib/mixins/template-stamp.html
index af17ee3bfe..6bafd2d484 100644
--- a/lib/mixins/template-stamp.html
+++ b/lib/mixins/template-stamp.html
@@ -118,8 +118,8 @@
      */
     class TemplateStamp extends superClass {
 
-      _initializeProperties() {
-        super._initializeProperties();
+      constructor() {
+        super();
         this.$ = null;
       }