diff --git a/phpBB/viewtopic.php b/phpBB/viewtopic.php
index 256bada0d9..99b875ae3d 100644
--- a/phpBB/viewtopic.php
+++ b/phpBB/viewtopic.php
@@ -1124,7 +1124,7 @@ while ($row = $db->sql_fetchrow($result))
 
 			$id_cache[] = $poster_id;
 
-			$user_cache[$poster_id] = array(
+			$user_cache_data = array(
 				'joined'		=> $user->format_date($row['user_regdate']),
 				'posts'			=> $row['user_posts'],
 				'warnings'		=> (isset($row['user_warnings'])) ? $row['user_warnings'] : 0,
@@ -1162,6 +1162,13 @@ while ($row = $db->sql_fetchrow($result))
 				'author_profile'	=> get_username_string('profile', $poster_id, $row['username'], $row['user_colour']),
 			);
 
+			$vars = array('user_cache_data', 'row', 'poster_id');
+			$event = new phpbb_event_data(compact($vars));
+			$phpbb_dispatcher->dispatch('core.viewtopic_user_cache', $event);
+			extract($event->get_data_filtered($vars));
+
+			$user_cache[$poster_id] = $user_cache_data;
+
 			get_user_rank($row['user_rank'], $row['user_posts'], $user_cache[$poster_id]['rank_title'], $user_cache[$poster_id]['rank_image'], $user_cache[$poster_id]['rank_image_src']);
 
 			if ((!empty($row['user_allow_viewemail']) && $auth->acl_get('u_sendemail')) || $auth->acl_get('a_email'))