diff --git a/ipc/mscom/Interceptor.h b/ipc/mscom/Interceptor.h
index 9a2cc81bfc0c..69b188ffcce3 100644
--- a/ipc/mscom/Interceptor.h
+++ b/ipc/mscom/Interceptor.h
@@ -112,7 +112,7 @@ private:
   };
 
 private:
-  Interceptor(IInterceptorSink* aSink);
+  explicit Interceptor(IInterceptorSink* aSink);
   ~Interceptor();
   HRESULT GetInitialInterceptorForIID(REFIID aTargetIid,
                                       STAUniquePtr<IUnknown> aTarget,