diff --git a/lib/Horde/Imap/Client/Socket.php b/lib/Horde/Imap/Client/Socket.php
index 12d6dfaee..c9042beb4 100644
--- a/lib/Horde/Imap/Client/Socket.php
+++ b/lib/Horde/Imap/Client/Socket.php
@@ -2952,7 +2952,7 @@ protected function _fetchCmd(
             case Horde_Imap_Client::FETCH_BODYPART:
             case Horde_Imap_Client::FETCH_HEADERS:
                 foreach ($c_val as $key => $val) {
-                    $cmd = ($key == 0)
+                    $cmd = ((int)$key == 0)
                         ? ''
                         : $key . '.';
                     $main_cmd = 'BODY';