diff --git a/src/Handlebars/Helpers.php b/src/Handlebars/Helpers.php
index c5046b0..5bf62dd 100644
--- a/src/Handlebars/Helpers.php
+++ b/src/Handlebars/Helpers.php
@@ -129,7 +129,7 @@ class Helpers
             );
         }
 
-        return $this->helpers[$name]($template, $context, $args, $source);
+        return call_user_func($this->helpers[$name], $template, $context, $args, $source);
     }
 
     /**