diff --git a/dom/webidl/MessageEvent.webidl b/dom/webidl/MessageEvent.webidl
index 558a2cbc1667..e4f4ceac60f7 100644
--- a/dom/webidl/MessageEvent.webidl
+++ b/dom/webidl/MessageEvent.webidl
@@ -7,7 +7,7 @@
  * https://html.spec.whatwg.org/#messageevent
  */
 
-[Exposed=(Window,Worker,AudioWorklet)]
+[Exposed=(Window,Worker,AudioWorklet), ProbablyShortLivingWrapper]
 interface MessageEvent : Event {
   constructor(DOMString type, optional MessageEventInit eventInitDict = {});