diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index 6bdea1c44..ec3024cbd 100644
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -1825,10 +1825,18 @@ class YoutubeTruncatedURLIE(InfoExtractor):
     IE_NAME = 'youtube:truncated_url'
     IE_DESC = False  # Do not list
     _VALID_URL = r'''(?x)
-        (?:https?://)?[^/]+/watch\?(?:feature=[a-z_]+)?$|
+        (?:https?://)?[^/]+/watch\?(?:
+            feature=[a-z_]+|
+            annotation_id=annotation_[^&]+
+        )?$|
         (?:https?://)?(?:www\.)?youtube\.com/attribution_link\?a=[^&]+$
     '''
 
+    _TESTS = [{
+        'url': 'http://www.youtube.com/watch?annotation_id=annotation_3951667041',
+        'only_matching': True,
+    }]
+
     def _real_extract(self, url):
         raise ExtractorError(
             u'Did you forget to quote the URL? Remember that & is a meta '