diff --git a/spine-c/spine-c/include/spine/AnimationState.h b/spine-c/spine-c/include/spine/AnimationState.h
index ebfba21f8..a2d68500d 100644
--- a/spine-c/spine-c/include/spine/AnimationState.h
+++ b/spine-c/spine-c/include/spine/AnimationState.h
@@ -64,6 +64,7 @@ struct spTrackEntry {
 	float* timelinesRotation;
 	int timelinesRotationCount;
 	void* rendererObject;
+	void* userData;
 
 #ifdef __cplusplus
 	spTrackEntry() :