diff --git a/booking.variety_form.inc b/booking.variety_form.inc
index 2e63877..d70d0b1 100644
--- a/booking.variety_form.inc
+++ b/booking.variety_form.inc
@@ -62,7 +62,7 @@ function booking_variety_regn_form($node, &$form_state)
   $form['variety-sessions'] = array(
     '#type' => 'fieldset',
     '#title' => 'Select Variety Sessions',
-    '#attributes' => array('class' => 'element-hidden'),
+    '#attributes' => array('class' => array('element-hidden')),
     //'#prefix' => '<div id="booking_variety_session_fieldset_wrapper">',
     //'#suffix' => '</div>'
   );