diff --git a/stepmania/src/Tween.h b/stepmania/src/Tween.h
index 55f3e185b7..efbfdf4033 100644
--- a/stepmania/src/Tween.h
+++ b/stepmania/src/Tween.h
@@ -13,7 +13,8 @@ enum TweenType
 	TWEEN_DECELERATE, 
 	TWEEN_SPRING,
 	TWEEN_BEZIER,
-	NUM_TweenType
+	NUM_TweenType,
+	TweenType_Invalid
 };
 #define FOREACH_TweenType( tt ) FOREACH_ENUM( TweenType, NUM_TweenType, tt )