diff --git a/src/kmmainwidget.h b/src/kmmainwidget.h
index b76f05430..97b44ea99 100644
--- a/src/kmmainwidget.h
+++ b/src/kmmainwidget.h
@@ -88,9 +88,6 @@ class SieveImapPasswordProvider;
 class ManageSieveScriptsDialog;
 class VacationManager;
 }
-namespace MessageViewer {
-class DKIMWidgetInfo;
-}
 namespace MailCommon {
 class FolderSelectionDialog;
 class FavoriteCollectionWidget;