diff --git a/moment/moment-node.d.ts b/moment/moment-node.d.ts
index 1c7267638c..48f00ed987 100644
--- a/moment/moment-node.d.ts
+++ b/moment/moment-node.d.ts
@@ -193,6 +193,7 @@ declare module moment {
         utc(): Moment; // current date/time in UTC mode
 
         isValid(): boolean;
+        invalidAt(): number;
 
         year(y: number): Moment;
         year(): number;