diff --git a/moment.d.ts b/moment.d.ts
index 60d31bf40b..24667a3f5a 100644
--- a/moment.d.ts
+++ b/moment.d.ts
@@ -154,6 +154,8 @@ declare namespace moment {
   }
 
   interface Duration {
+    clone(): Duration;
+
     humanize(withSuffix?: boolean): string;
 
     abs(): Duration;
diff --git a/typing-tests/moment-tests.ts b/typing-tests/moment-tests.ts
index 3b7362364c..af635ca7cf 100644
--- a/typing-tests/moment-tests.ts
+++ b/typing-tests/moment-tests.ts
@@ -256,6 +256,7 @@ moment.duration({
     M: 2,
     y: 2,
 });
+moment.duration(1, "minute").clone();
 moment.duration(1, "minutes").humanize();
 moment.duration(500).milliseconds();
 moment.duration(500).asMilliseconds();