diff --git a/phpBB/includes/acp/acp_groups.php b/phpBB/includes/acp/acp_groups.php
index e0f2e0ed8d..449c905bfa 100644
--- a/phpBB/includes/acp/acp_groups.php
+++ b/phpBB/includes/acp/acp_groups.php
@@ -327,7 +327,7 @@ class acp_groups
 					$avatar_data = \phpbb\avatar\manager::clean_row($group_row);
 					if (!isset($avatar_data['id']))
 					{
-						$avatar_data['id'] = $group_id;
+						$avatar_data['id'] = 'g' . $group_id;
 					}
 				}