diff --git a/yt_dlp/extractor/redtube.py b/yt_dlp/extractor/redtube.py
index 172c31b39..36d530daf 100644
--- a/yt_dlp/extractor/redtube.py
+++ b/yt_dlp/extractor/redtube.py
@@ -7,6 +7,7 @@ from ..utils import (
     str_to_int,
     unified_strdate,
     url_or_none,
+    urljoin,
 )
 
 
@@ -79,7 +80,7 @@ class RedTubeIE(InfoExtractor):
                 'media definitions', default='{}'),
             video_id, fatal=False)
         for media in medias if isinstance(medias, list) else []:
-            format_url = url_or_none(media.get('videoUrl'))
+            format_url = urljoin('https://www.redtube.com', media.get('videoUrl'))
             if not format_url:
                 continue
             format_id = media.get('format')