diff --git a/src/script/lua_api/l_async_events.h b/src/script/lua_api/l_async_events.h
index 4aaf3bdfe..347d9c0fc 100644
--- a/src/script/lua_api/l_async_events.h
+++ b/src/script/lua_api/l_async_events.h
@@ -132,7 +132,7 @@ private:
 
 /** asynchornous thread and job management **/
 class AsyncEngine {
-	friend AsyncWorkerThread;
+	friend class AsyncWorkerThread;
 public:
 	/**
 	 * default constructor