diff --git a/lib/Cake/Test/Case/Utility/CakeTimeTest.php b/lib/Cake/Test/Case/Utility/CakeTimeTest.php
index 51c788e69..28ccb40aa 100644
--- a/lib/Cake/Test/Case/Utility/CakeTimeTest.php
+++ b/lib/Cake/Test/Case/Utility/CakeTimeTest.php
@@ -816,6 +816,13 @@ class CakeTimeTest extends CakeTestCase {
 		$result = $this->Time->fromString('+1 hour', $timezone);
 		$expected = $this->Time->convert(strtotime('+1 hour'), $timezone);
 		$this->assertEquals($expected, $result);
+
+		date_default_timezone_set('UTC');
+		$date = new DateTime('now', new DateTimeZone('Europe/London'));
+		$this->Time->fromString($date);
+		$this->assertEquals('Europe/London', $date->getTimeZone()->getName());
+
+		$this->_restoreSystemTimezone();
 	}
 
 /**
diff --git a/lib/Cake/Utility/CakeTime.php b/lib/Cake/Utility/CakeTime.php
index f01154412..d2e3c6ffb 100644
--- a/lib/Cake/Utility/CakeTime.php
+++ b/lib/Cake/Utility/CakeTime.php
@@ -315,8 +315,9 @@ class CakeTime {
 		if (is_integer($dateString) || is_numeric($dateString)) {
 			$date = intval($dateString);
 		} elseif (is_object($dateString) && $dateString instanceof DateTime) {
-			$dateString->setTimezone(new DateTimeZone(date_default_timezone_get()));
-			$date = (int)$dateString->format('U') + $dateString->getOffset();
+			$clone = clone $dateString;
+			$clone->setTimezone(new DateTimeZone(date_default_timezone_get()));
+			$date = (int)$clone->format('U') + $clone->getOffset();
 		} else {
 			$date = strtotime($dateString);
 		}