diff --git a/lib/util.js b/lib/util.js
index c00b4ad2cc7..401d55bbe82 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -13,6 +13,8 @@ exports.format = function(f) {
     return objects.join(' ');
   }
 
+  if (arguments.length === 1) return f;
+
   var i = 1;
   var args = arguments;
   var len = args.length;