diff --git a/src/core/sprites/Sprite.js b/src/core/sprites/Sprite.js
index 5fdf224..bf07021 100644
--- a/src/core/sprites/Sprite.js
+++ b/src/core/sprites/Sprite.js
@@ -31,7 +31,7 @@
      *
      * @member {PIXI.Point}
      */
-    this.anchor = new math.Point();
+    this.anchor = new math.ObservablePoint(this.onAnchorUpdate, this);
 
     /**
      * The texture that the sprite is using
@@ -200,6 +200,11 @@
     }
 };
 
+Sprite.prototype.onAnchorUpdate = function()
+{
+    this._transformID = -1;
+}
+
 Sprite.prototype.calculateVertices = function ()
 {
     if(this._transformID === this.transform._worldID && !this.textureDirty)