diff --git a/underscore.string/underscore.string.d.ts b/underscore.string/underscore.string.d.ts
index 38271f3de..1b08dcf85 100644
--- a/underscore.string/underscore.string.d.ts
+++ b/underscore.string/underscore.string.d.ts
@@ -10,6 +10,8 @@ interface UnderscoreStatic {
     string: UnderscoreStringStatic;
 }
 
+declare var s : UnderscoreStringStatic;
+
 interface UnderscoreStringStatic extends UnderscoreStringStaticExports {
     /**
      * Tests if string contains a substring.