diff --git a/youtube_dl/YoutubeDL.py b/youtube_dl/YoutubeDL.py
index fe30758ef..69736acff 100755
--- a/youtube_dl/YoutubeDL.py
+++ b/youtube_dl/YoutubeDL.py
@@ -1529,7 +1529,7 @@ class YoutubeDL(object):
                 # see http://bugs.python.org/issue1646728)
                 try:
                     upload_date = datetime.datetime.utcfromtimestamp(info_dict[ts_key])
-                    info_dict[date_key] = upload_date.strftime('%Y%m%d')
+                    info_dict[date_key] = compat_str(upload_date.strftime('%Y%m%d'))
                 except (ValueError, OverflowError, OSError):
                     pass