diff --git a/zerver/lib/bugdown/__init__.py b/zerver/lib/bugdown/__init__.py
index 310903df4a..02b72b0538 100644
--- a/zerver/lib/bugdown/__init__.py
+++ b/zerver/lib/bugdown/__init__.py
@@ -338,7 +338,8 @@ class InlineInterestingLinkProcessor(markdown.treeprocessors.Treeprocessor):
             return None
         # Youtube video id extraction regular expression from http://pastebin.com/KyKAFv1s
         # If it matches, match.group(2) is the video id.
-        youtube_re = r'^((?:https?://)?(?:youtu\.be/|(?:\w+\.)?youtube(?:-nocookie)?\.com/)(?:(?:(?:v|embed)/)|(?:(?:watch(?:_popup)?(?:\.php)?)?(?:\?|#!?)(?:.+&)?v=)))?([0-9A-Za-z_-]+)(?(1).+)?$'
+        youtube_re = r'^((?:https?://)?(?:youtu\.be/|(?:\w+\.)?youtube(?:-nocookie)?\.com/)' + \
+                     r'(?:(?:(?:v|embed)/)|(?:(?:watch(?:_popup)?(?:\.php)?)?(?:\?|#!?)(?:.+&)?v=)))?([0-9A-Za-z_-]+)(?(1).+)?$'
         match = re.match(youtube_re, url)
         if match is None:
             return None