diff --git a/moment/moment.d.ts b/moment/moment.d.ts
index 834cc0462..303a41099 100644
--- a/moment/moment.d.ts
+++ b/moment/moment.d.ts
@@ -325,7 +325,7 @@ declare module moment {
       weekdays?: any;
       weekdaysShort?: any;
       weekdaysMin?: any;
-      longDateFormat?: MomentLongDateFormat;
+      longDateFormat(formatType: string): string;
       relativeTime?: MomentRelativeTime;
       meridiem?: (hour: number, minute: number, isLowercase: boolean) => string;
       calendar?: MomentCalendar;