diff --git a/yt_dlp/extractor/fc2.py b/yt_dlp/extractor/fc2.py
index b892c2357e..4765626901 100644
--- a/yt_dlp/extractor/fc2.py
+++ b/yt_dlp/extractor/fc2.py
@@ -24,7 +24,7 @@ class FC2IE(InfoExtractor):
             'id': '20121103kUan1KHs',
             'title': 'Boxing again with Puff',
             'ext': 'mp4',
-            'thumbnail': 're:https?://.+\.jpe?g',
+            'thumbnail': 're:https?://.+\\.jpe?g',
         },
         'file_minsize': 633,
         'params': {
@@ -39,7 +39,7 @@ class FC2IE(InfoExtractor):
             'id': '20121129xMeT3Czt',
             'title': 'Rotfux',
             'ext': 'mp4',
-            'thumbnail': 're:https?://.+\.jpe?g',
+            'thumbnail': 're:https?://.+\\.jpe?g',
             'description': 'Rotfux',
         },
     }, {