diff --git a/common/thorhelper/thorcommon.hpp b/common/thorhelper/thorcommon.hpp
index 02dbeaa839e..baab17d66be 100644
--- a/common/thorhelper/thorcommon.hpp
+++ b/common/thorhelper/thorcommon.hpp
@@ -233,7 +233,7 @@ extern THORHELPER_API IDiskMerger *createDiskMerger(IRowInterfaces *rowInterface
 
 class THORHELPER_API ActivityTimeAccumulator
 {
-    friend struct ActivityTimer;
+    friend class ActivityTimer;
 public:
     ActivityTimeAccumulator()
     {