diff --git a/cake/libs/set.php b/cake/libs/set.php
index 5da018f32..705074cb2 100644
--- a/cake/libs/set.php
+++ b/cake/libs/set.php
@@ -257,7 +257,7 @@ class Set extends Object {
 			$val1 = $this->get();
 		}
 		if (is_object($val2) && (is_a($val2, 'set') || is_a($val2, 'Set'))) {
-
+			$val2 = $val2->get();
 		}
 
 		$out = array();