diff --git a/include/etl/fsm.h b/include/etl/fsm.h
index bb4d21f9..19b3bb55 100644
--- a/include/etl/fsm.h
+++ b/include/etl/fsm.h
@@ -325,7 +325,7 @@ namespace etl
   {
   public:
 
-    friend etl::hfsm;
+    friend class etl::hfsm;
     using imessage_router::receive;
 
     //*******************************************