diff --git a/lib/Doctrine/ORM/QueryBuilder.php b/lib/Doctrine/ORM/QueryBuilder.php
index 27f65e14c..436522b69 100644
--- a/lib/Doctrine/ORM/QueryBuilder.php
+++ b/lib/Doctrine/ORM/QueryBuilder.php
@@ -932,4 +932,24 @@ class QueryBuilder
     {
         return $this->getDQL();
     }
+
+    /**
+     * Deep clone of all expression objects in the DQL parts.
+     *
+     * @return void
+     */
+    public function __clone()
+    {
+        foreach ($this->_dqlParts AS $part => $elements) {
+            if (is_array($this->_dqlParts[$part])) {
+                foreach ($this->_dqlParts[$part] AS $idx => $element) {
+                    if (is_object($element)) {
+                        $this->_dqlParts[$part][$idx] = clone $element;
+                    }
+                }
+            } else if (\is_object($elements)) {
+                $this->_dqlParts[$part] = clone $elements;
+            }
+        }
+    }
 }
\ No newline at end of file
diff --git a/tests/Doctrine/Tests/ORM/QueryBuilderTest.php b/tests/Doctrine/Tests/ORM/QueryBuilderTest.php
index 1ad039bb9..f18516fc4 100644
--- a/tests/Doctrine/Tests/ORM/QueryBuilderTest.php
+++ b/tests/Doctrine/Tests/ORM/QueryBuilderTest.php
@@ -569,4 +569,24 @@ class QueryBuilderTest extends \Doctrine\Tests\OrmTestCase
         $this->assertNull($qb->getDQLPart('where'));
         $this->assertEquals(0, count($qb->getDQLPart('orderBy')));
     }
+
+    /**
+     * @group DDC-867
+     */
+    public function testDeepClone()
+    {
+        $qb = $this->_em->createQueryBuilder()
+            ->select('u')
+            ->from('Doctrine\Tests\Models\CMS\CmsUser', 'u')
+            ->andWhere('u.username = ?1')
+            ->andWhere('u.status = ?2');
+
+        $expr = $qb->getDQLPart('where');
+        $this->assertEquals(2, $expr->count(), "Modifying the second query should affect the first one.");
+        
+        $qb2 = clone $qb;
+        $qb2->andWhere('u.name = ?3');
+
+        $this->assertEquals(2, $expr->count(), "Modifying the second query should affect the first one.");
+    }
 }
\ No newline at end of file