diff --git a/paper-tooltip.html b/paper-tooltip.html
index abd74a9..9c7343b 100644
--- a/paper-tooltip.html
+++ b/paper-tooltip.html
@@ -267,6 +267,7 @@
         this.toggleClass('hidden', false, this.$.tooltip);
         this.updatePosition();
 
+        this.animationConfig.entry[0].timing = this.animationConfig.entry[0].timing || {};
         this.animationConfig.entry[0].timing.delay = this.animationDelay;
         this._animationPlaying = true;
         this.playAnimation('entry');