diff --git a/moment/moment-node.d.ts b/moment/moment-node.d.ts
index 3728f898f7..9781e93683 100644
--- a/moment/moment-node.d.ts
+++ b/moment/moment-node.d.ts
@@ -401,6 +401,7 @@ declare module moment {
         unix(timestamp: number): Moment;
 
         invalid(parsingFlags?: Object): Moment;
+        invalidAt(): number;
         isMoment(): boolean;
         isMoment(m: any): boolean;
         isDate(m: any): boolean;