diff --git a/relocate.php b/relocate.php
index 3d1383e..8475b33 100644
--- a/relocate.php
+++ b/relocate.php
@@ -37,7 +37,9 @@ function relocate_array($array) {
     $result = array();
 
     foreach ($array as $key => $value) {
-        $key = relocate_string($key);
+        if (is_string($key)) {
+            $key = relocate_string($key);
+        }
         $result[$key] = relocate_value($value);
     }