diff --git a/cake/libs/controller/controller.php b/cake/libs/controller/controller.php
index 37e33b824..6ceeb0b22 100644
--- a/cake/libs/controller/controller.php
+++ b/cake/libs/controller/controller.php
@@ -939,7 +939,7 @@ class Controller extends Object {
 			if ($_hour != 12 && (isset($this->data[$modelClass][$field['name'] . '_meridian']) && 'pm' == $this->data[$modelClass][$field['name'] . '_meridian'])) {
 				$_hour = $_hour + 12;
 			}
-			if ($hour == 12 && 'am' == $this->data[$modelName][$field['name'] . '_meridian']) {
+			if ($hour == 12 && (isset($this->data[$modelClass][$field['name'] . '_meridian']) && 'am' == $this->data[$modelName][$field['name'] . '_meridian']) {
 			     $hour = '00';
 			}
 			unset($this->data[$modelClass][$field['name'] . '_meridian']);