diff --git modules/field/views_handler_field_field.inc modules/field/views_handler_field_field.inc
index 2beaec5..6cdfdfc 100644
--- modules/field/views_handler_field_field.inc
+++ modules/field/views_handler_field_field.inc
@@ -189,7 +189,7 @@ class views_handler_field_field extends views_handler_field {
         $object = new stdClass();
         $object->{$entity_info['entity keys']['id']} = $row->{$this->field_alias};
         // Not every entity type has bundle and revision.
-        $bundle = '';
+        $bundle = NULL;
         if (!empty($entity_info['entity keys']['bundle'])) {
           $object->{$entity_info['entity keys']['bundle']} = $bundle = $row->{$this->aliases[$this->definition['field_name'] . '_bundle']};
         }