diff --git a/core/ldap_api.php b/core/ldap_api.php
index 18dbc2977a..5d7688b527 100644
--- a/core/ldap_api.php
+++ b/core/ldap_api.php
@@ -396,7 +396,7 @@ function ldap_authenticate_by_username( $p_username, $p_password ) {
 			$t_fields_to_update = array('password' => md5( $p_password ));
 
 			if( ON == config_get( 'use_ldap_realname' ) ) {
-				$t_fields_to_update['realname'] = ldap_realname( $t_user_id );
+				$t_fields_to_update['realname'] = ldap_realname_from_username( $p_username );
 			}
 
 			if( ON == config_get( 'use_ldap_email' ) ) {