diff --git a/src/Symfony/Component/Validator/ConstraintProviderInterface.php b/src/Symfony/Component/Validator/ConstraintProviderInterface.php
new file mode 100644
index 0000000000..c081d3ad13
--- /dev/null
+++ b/src/Symfony/Component/Validator/ConstraintProviderInterface.php
@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+ 
+namespace Symfony\Component\Validator;
+
+use Symfony\Component\Validator\Mapping\ClassMetadata;
+
+/**
+ * Makes it possible to define dynamic constraints for an object.
+ */
+interface ConstraintProviderInterface
+{
+    /**
+     * Lets the user create dynamic constraints
+     *
+     * @param Mapping\ClassMetadata
+     */
+    function loadDynamicValidatorMetadata(ClassMetadata $metadata);
+}
diff --git a/src/Symfony/Component/Validator/Validator.php b/src/Symfony/Component/Validator/Validator.php
index d20a623256..2327aa1c0b 100644
--- a/src/Symfony/Component/Validator/Validator.php
+++ b/src/Symfony/Component/Validator/Validator.php
@@ -12,6 +12,7 @@
 namespace Symfony\Component\Validator;
 
 use Symfony\Component\Validator\Mapping\ClassMetadataFactoryInterface;
+use Symfony\Component\Validator\Mapping\ClassMetadata;
 
 /**
  * The default implementation of the ValidatorInterface.
@@ -57,6 +58,13 @@ class Validator implements ValidatorInterface
     public function validate($object, $groups = null)
     {
         $metadata = $this->metadataFactory->getClassMetadata(get_class($object));
+        
+        if ($object instanceof ConstraintProviderInterface) {
+            $dynamicMetadata = new ClassMetadata(get_class($object));
+            $dynamicMetadata->mergeConstraints($metadata);
+            $object->loadDynamicValidatorMetadata($dynamicMetadata);
+            $metadata = $dynamicMetadata;
+        }
 
         $walk = function(GraphWalker $walker, $group) use ($metadata, $object) {
             return $walker->walkObject($metadata, $object, $group, '');
diff --git a/tests/Symfony/Tests/Component/Validator/Fixtures/DynamicConstraintsEntity.php b/tests/Symfony/Tests/Component/Validator/Fixtures/DynamicConstraintsEntity.php
new file mode 100644
index 0000000000..41bfe44d39
--- /dev/null
+++ b/tests/Symfony/Tests/Component/Validator/Fixtures/DynamicConstraintsEntity.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace Symfony\Tests\Component\Validator\Fixtures;
+
+use Symfony\Component\Validator\ConstraintProviderInterface;
+use Symfony\Component\Validator\Mapping\ClassMetadata;
+
+class DynamicConstraintsEntity implements ConstraintProviderInterface
+{
+    protected $validationEnabled = false;
+    protected $firstValue;
+    
+    public function setValidation($enabled)
+    {
+        $this->validationEnabled = $enabled;
+    }
+    
+    public function getSecondValue() 
+    {
+        return null;
+    }
+    
+    public function loadDynamicValidatorMetadata(ClassMetadata $metadata)
+    {
+        if ($this->validationEnabled) {
+            $metadata->addPropertyConstraint('firstValue', new FailingConstraint());
+            $metadata->addGetterConstraint('secondValue', new FailingConstraint());
+        }
+    }
+}
diff --git a/tests/Symfony/Tests/Component/Validator/ValidatorTest.php b/tests/Symfony/Tests/Component/Validator/ValidatorTest.php
index 86c8ee98a6..38af8e31ba 100644
--- a/tests/Symfony/Tests/Component/Validator/ValidatorTest.php
+++ b/tests/Symfony/Tests/Component/Validator/ValidatorTest.php
@@ -15,10 +15,12 @@ require_once __DIR__.'/Fixtures/Entity.php';
 require_once __DIR__.'/Fixtures/FailingConstraint.php';
 require_once __DIR__.'/Fixtures/FailingConstraintValidator.php';
 require_once __DIR__.'/Fixtures/FakeClassMetadataFactory.php';
+require_once __DIR__.'/Fixtures/DynamicConstraintsEntity.php';
 
 use Symfony\Tests\Component\Validator\Fixtures\Entity;
 use Symfony\Tests\Component\Validator\Fixtures\FakeClassMetadataFactory;
 use Symfony\Tests\Component\Validator\Fixtures\FailingConstraint;
+use Symfony\Tests\Component\Validator\Fixtures\DynamicConstraintsEntity;
 use Symfony\Component\Validator\Validator;
 use Symfony\Component\Validator\ConstraintViolation;
 use Symfony\Component\Validator\ConstraintViolationList;
@@ -121,6 +123,38 @@ class ValidatorTest extends \PHPUnit_Framework_TestCase
 
         $this->assertEquals($violations, $result);
     }
+    
+    public function testValidate_constraintProvider()
+    {
+        $entity = new DynamicConstraintsEntity();
+        $metadata = new ClassMetadata(get_class($entity));
+        $this->factory->addClassMetadata($metadata);
+        
+        $entity->setValidation(true);
+
+        $violations = new ConstraintViolationList();
+        $violations->add(new ConstraintViolation(
+            '',
+            array(),
+            $entity,
+            'firstValue',
+            ''
+        ));
+        $violations->add(new ConstraintViolation(
+            '',
+            array(),
+            $entity,
+            'secondValue',
+            ''
+        ));
+        
+        $this->assertEquals($violations, $this->validator->validate($entity));
+        
+        $entity->setValidation(false);
+        
+        $violations = new ConstraintViolationList();
+        $this->assertEquals($violations, $this->validator->validate($entity));
+    }
 
     public function testValidateProperty()
     {