diff --git a/dom/media/gmp/GMPServiceParent.h b/dom/media/gmp/GMPServiceParent.h
index fd8d6ec6ce37..a3fcc09d09a0 100644
--- a/dom/media/gmp/GMPServiceParent.h
+++ b/dom/media/gmp/GMPServiceParent.h
@@ -197,7 +197,7 @@ public:
                                             bool* aHasPlugin,
                                             nsCString* aVersion);
 
-  virtual void ActorDestroy(ActorDestroyReason aWhy);
+  virtual void ActorDestroy(ActorDestroyReason aWhy) override;
 
   static PGMPServiceParent* Create(Transport* aTransport, ProcessId aOtherPid);