diff --git a/js/ui/environment.js b/js/ui/environment.js
index e22ec7402..f70394710 100644
--- a/js/ui/environment.js
+++ b/js/ui/environment.js
@@ -96,6 +96,15 @@ function init() {
     Clutter.Actor.prototype.toString = function() {
         return St.describe_actor(this);
     };
+    // Deprecation warning for former JS classes turned into an actor subclass
+    Object.defineProperty(Clutter.Actor.prototype, 'actor', {
+        get() {
+            let klass = this.constructor.name;
+            let { stack } = new Error();
+            log(`Usage of object.actor is deprecated for ${klass}\n${stack}`);
+            return this;
+        }
+    });
 
     let origToString = Object.prototype.toString;
     Object.prototype.toString = function() {