diff --git a/toolkit/components/telemetry/TelemetryPing.js b/toolkit/components/telemetry/TelemetryPing.js
index 4cdbe668aea..56a4e265efa 100644
--- a/toolkit/components/telemetry/TelemetryPing.js
+++ b/toolkit/components/telemetry/TelemetryPing.js
@@ -1077,7 +1077,7 @@ TelemetryPing.prototype = {
   },
 
   classID: Components.ID("{55d6a5fa-130e-4ee6-a158-0133af3b86ba}"),
-  QueryInterface: XPCOMUtils.generateQI([Ci.nsITelemetryPing]),
+  QueryInterface: XPCOMUtils.generateQI([Ci.nsITelemetryPing, Ci.nsIObserver]),
 };
 
 this.NSGetFactory = XPCOMUtils.generateNSGetFactory([TelemetryPing]);