diff --git a/gstreamer-video/src/video_time_code.rs b/gstreamer-video/src/video_time_code.rs
index ca8876f3a..963ca9e0f 100644
--- a/gstreamer-video/src/video_time_code.rs
+++ b/gstreamer-video/src/video_time_code.rs
@@ -239,6 +239,7 @@ impl ValidVideoTimeCode {
     }
 
     #[doc(alias = "gst_video_time_code_add_interval")]
+    #[must_use = "this returns the result of the operation, without modifying the original"]
     pub fn add_interval(
         &self,
         tc_inter: &VideoTimeCodeInterval,