diff --git a/moment/moment-external-tests.ts b/moment/moment-external-tests.ts
index 9c61168921..2fbdbb6e71 100644
--- a/moment/moment-external-tests.ts
+++ b/moment/moment-external-tests.ts
@@ -210,6 +210,12 @@ moment.duration(500).asSeconds();
 moment.duration().minutes();
 moment.duration().asMinutes();
 
+var adur = moment.duration(3, 'd');
+var bdur = moment.duration(2, 'd');
+adur.subtract(bdur).days();
+adur.subtract(1).days();
+adur.subtract(1, 'd').days();
+
 // Defining a custom language: 
 moment.lang('en', {
     months: ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"],
diff --git a/moment/moment-tests.ts b/moment/moment-tests.ts
index 68a718a33d..1c8b7c82cf 100644
--- a/moment/moment-tests.ts
+++ b/moment/moment-tests.ts
@@ -208,6 +208,12 @@ moment.duration(500).asSeconds();
 moment.duration().minutes();
 moment.duration().asMinutes();
 
+var adur = moment.duration(3, 'd');
+var bdur = moment.duration(2, 'd');
+adur.subtract(bdur).days();
+adur.subtract(1).days();
+adur.subtract(1, 'd').days();
+
 // Defining a custom language: 
 moment.lang('en', {
     months: ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"],
diff --git a/moment/moment.d.ts b/moment/moment.d.ts
index cfc19100bf..f997026fd2 100644
--- a/moment/moment.d.ts
+++ b/moment/moment.d.ts
@@ -50,6 +50,9 @@ interface Duration {
     years(): number;
     asYears(): number;
 
+    subtract(n: number, p: string): Duration;
+    subtract(n: number): Duration;
+    subtract(d: Duration): Duration;
 }
 
 interface Moment {