diff --git a/src/core/feeddownloader.h b/src/core/feeddownloader.h
index 02683b28b..3a8cd6839 100755
--- a/src/core/feeddownloader.h
+++ b/src/core/feeddownloader.h
@@ -27,6 +27,7 @@
 
 class Feed;
 class QThreadPool;
+class QMutex;
 
 // Represents results of batch feed updates.
 class FeedDownloadResults {