diff --git a/spine-as3/spine-as3/src/spine/AnimationStateData.as b/spine-as3/spine-as3/src/spine/AnimationStateData.as
index fce61ae39..3841b7fa9 100644
--- a/spine-as3/spine-as3/src/spine/AnimationStateData.as
+++ b/spine-as3/spine-as3/src/spine/AnimationStateData.as
@@ -4,7 +4,7 @@ import spine.animation.Animation;
 public class AnimationStateData {
 	private var _skeletonData:SkeletonData;
 	private var animationToMixTime:Object = new Object();
-	public var defaultMix:Number;
+	public var defaultMix:Number = 0;
 
 	public function AnimationStateData (skeletonData:SkeletonData) {
 		_skeletonData = skeletonData;