diff --git a/src/tooltip/tooltip.js b/src/tooltip/tooltip.js
index de6d66dc16..9f800e6d4f 100644
--- a/src/tooltip/tooltip.js
+++ b/src/tooltip/tooltip.js
@@ -167,7 +167,10 @@ angular.module( 'ui.bootstrap.tooltip', [ 'ui.bootstrap.position', 'ui.bootstrap
             // Show the tooltip popup element.
             function show() {
 
-              popupTimeout = null;
+              if ( popupTimeout ) {
+                $timeout.cancel( popupTimeout );
+                popupTimeout = null;
+              }
 
               // If there is a pending remove transition, we must cancel it, lest the
               // tooltip be mysteriously removed.