diff --git a/library/Director/Objects/IcingaObjectGroups.php b/library/Director/Objects/IcingaObjectGroups.php
index 8bef1b195..f42883104 100644
--- a/library/Director/Objects/IcingaObjectGroups.php
+++ b/library/Director/Objects/IcingaObjectGroups.php
@@ -183,6 +183,10 @@ public function add($group, $onError = 'fail')
             return $this;
         }
 
+        if (is_int($group)) {
+            $group = (string) $group;
+        }
+
         /** @var IcingaObjectGroup $class */
         $class = $this->getGroupClass();