diff --git a/src/Illuminate/Routing/UrlGenerator.php b/src/Illuminate/Routing/UrlGenerator.php
index dac9c06b257b..9d360f651c5d 100755
--- a/src/Illuminate/Routing/UrlGenerator.php
+++ b/src/Illuminate/Routing/UrlGenerator.php
@@ -518,6 +518,8 @@ protected function getRouteScheme($route)
 	 * @param  mixed   $parameters
 	 * @param  bool    $absolute
 	 * @return string
+	 * 
+	 * @throws \InvalidArgumentException
 	 */
 	public function action($action, $parameters = array(), $absolute = true)
 	{
@@ -529,8 +531,13 @@ public function action($action, $parameters = array(), $absolute = true)
 		{
 			$action = trim($action, '\\');
 		}
-
-		return $this->toRoute($this->routes->getByAction($action), $parameters, $absolute);
+	
+		if ( ! is_null($route = $this->routes->getByAction($action)))
+		{
+			 return $this->toRoute($route, $parameters, $absolute);
+		}
+		
+		throw new InvalidArgumentException("Action {$action} not defined.");
 	}
 
 	/**