diff --git a/src/conf.py b/src/conf.py
index b99feecf4..8015ae60a 100644
--- a/src/conf.py
+++ b/src/conf.py
@@ -374,7 +374,8 @@ registerChannelValue(supybot.reply.format, 'time',
 def timestamp(t):
     if t is None:
         t = time.time()
-    t = time.localtime(t)
+    elif isinstance(t, int):
+        t = time.localtime(t)
     format = get(supybot.reply.format.time, dynamic.channel)
     return time.strftime(format, t)
 utils.str.timestamp = timestamp