diff --git a/modules/forum.module b/modules/forum.module
index 5b53a8305ff..3b9aa295f27 100644
--- a/modules/forum.module
+++ b/modules/forum.module
@@ -316,7 +316,7 @@ function _forum_last_reply($nid) {
 }
 
 function _forum_format($topic) {
-  if ($topic) {
+  if ($topic && $topic->timestamp) {
     return t('%time ago<br />by %author', array('%time' => format_interval(time() - $topic->timestamp), '%author' => format_name($topic)));
   }
   else {
diff --git a/modules/forum/forum.module b/modules/forum/forum.module
index 5b53a8305ff..3b9aa295f27 100644
--- a/modules/forum/forum.module
+++ b/modules/forum/forum.module
@@ -316,7 +316,7 @@ function _forum_last_reply($nid) {
 }
 
 function _forum_format($topic) {
-  if ($topic) {
+  if ($topic && $topic->timestamp) {
     return t('%time ago<br />by %author', array('%time' => format_interval(time() - $topic->timestamp), '%author' => format_name($topic)));
   }
   else {