diff --git a/freepik_cli/api/videos.py b/freepik_cli/api/videos.py
index e50bed9..3bd4d6d 100644
--- a/freepik_cli/api/videos.py
+++ b/freepik_cli/api/videos.py
@@ -35,7 +35,7 @@ class VideoAPI:
         if prompt:
             payload["prompt"] = prompt
         if duration:
-            payload["duration"] = duration
+            payload["duration"] = str(duration)
         if aspect_ratio:
             payload["aspect_ratio"] = aspect_ratio
         if seed is not None: