diff --git a/src/interface/window.h b/src/interface/window.h
index 9dc4c8697d..a8e2498dd8 100644
--- a/src/interface/window.h
+++ b/src/interface/window.h
@@ -32,6 +32,7 @@
 struct rct_window;
 union rct_window_event;
 struct track_design_file_ref;
+struct TitleSequence;
 
 extern uint16 TextInputDescriptionArgs[4];
 extern char gTextBoxInput[512];