diff --git a/link.module b/link.module
index 9e52de5..a1e8b56 100644
--- a/link.module
+++ b/link.module
@@ -64,7 +64,7 @@ function link_field_instance_settings_form($field, $instance) {
   $form = array(
     '#element_validate' => array('link_field_settings_form_validate'),
   );
-  
+
   $form['validate_url'] = array(
     '#type' => 'checkbox',
     '#title' => t('Validate URL'),
@@ -667,6 +667,11 @@ function theme_link_formatter_link_default($vars) {
   $link_options = $vars['element'];
   unset($link_options['element']['title']);
   unset($link_options['element']['url']);
+
+  if (isset($link_options['attributes']['class'])) {
+    $link_options['attributes']['class'] = array($link_options['attributes']['class']);
+  }
+
   // Display a normal link if both title and URL are available.
   if (!empty($vars['element']['title']) && !empty($vars['element']['url'])) {
     return l($vars['element']['title'], $vars['element']['url'], $link_options);