diff --git a/globalize/globalize.d.ts b/globalize/globalize.d.ts
index 902236ced0..8b4a1ce97a 100644
--- a/globalize/globalize.d.ts
+++ b/globalize/globalize.d.ts
@@ -110,11 +110,11 @@ class GlobalizeStatic {
     addCultureInfo(cultureName, baseCultureName, info? );
     findClosestCulture(cultureSelector: string);
     format(value, format, cultureSelector? );
-    localize(key, cultureSelector);
+    localize(key, cultureSelector?);
 
     parseDate(value: string, formats? , cultureSelector?: string): Date;
     parseInt(value: string, radix? , cultureSelector?: string): number;
     parseFloat(value: string, radix? , cultureSelector?: string): number;
 }
 
-declare var Globalize: GlobalizeStatic;
\ No newline at end of file
+declare var Globalize: GlobalizeStatic;