diff --git a/lib/Doctrine/ORM/EntityManagerInterface.php b/lib/Doctrine/ORM/EntityManagerInterface.php
index 1ac153f8bb0..33479c2a0be 100644
--- a/lib/Doctrine/ORM/EntityManagerInterface.php
+++ b/lib/Doctrine/ORM/EntityManagerInterface.php
@@ -21,6 +21,7 @@
 namespace Doctrine\ORM;
 
 use BadMethodCallException;
+use DateTimeInterface;
 use Doctrine\Common\EventManager;
 use Doctrine\DBAL\Connection;
 use Doctrine\ORM\Internal\Hydration\AbstractHydrator;
@@ -213,9 +214,9 @@ public function copy($entity, $deep = false);
     /**
      * Acquire a lock on the given entity.
      *
-     * @param object   $entity
-     * @param int      $lockMode
-     * @param int|null $lockVersion
+     * @param object                     $entity
+     * @param int                        $lockMode
+     * @param int|DateTimeInterface|null $lockVersion
      *
      * @return void
      *
diff --git a/lib/Doctrine/ORM/OptimisticLockException.php b/lib/Doctrine/ORM/OptimisticLockException.php
index cd00ef4d34e..a5d47bfefe5 100644
--- a/lib/Doctrine/ORM/OptimisticLockException.php
+++ b/lib/Doctrine/ORM/OptimisticLockException.php
@@ -20,7 +20,7 @@
 
 namespace Doctrine\ORM;
 
-use DateTime;
+use DateTimeInterface;
 
 /**
  * An OptimisticLockException is thrown when a version check on an object
@@ -70,8 +70,8 @@ public static function lockFailed($entity)
      */
     public static function lockFailedVersionMismatch($entity, $expectedLockVersion, $actualLockVersion)
     {
-        $expectedLockVersion = $expectedLockVersion instanceof DateTime ? $expectedLockVersion->getTimestamp() : $expectedLockVersion;
-        $actualLockVersion   = $actualLockVersion instanceof DateTime ? $actualLockVersion->getTimestamp() : $actualLockVersion;
+        $expectedLockVersion = $expectedLockVersion instanceof DateTimeInterface ? $expectedLockVersion->getTimestamp() : $expectedLockVersion;
+        $actualLockVersion   = $actualLockVersion instanceof DateTimeInterface ? $actualLockVersion->getTimestamp() : $actualLockVersion;
 
         return new self('The optimistic lock failed, version ' . $expectedLockVersion . ' was expected, but is actually ' . $actualLockVersion, $entity);
     }
diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index 7151cab8356..0b5212bc7e1 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -20,6 +20,7 @@
 
 namespace Doctrine\ORM;
 
+use DateTimeInterface;
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
 use Doctrine\Common\EventManager;
@@ -2456,9 +2457,9 @@ static function ($assoc) {
     /**
      * Acquire a lock on the given entity.
      *
-     * @param object $entity
-     * @param int    $lockMode
-     * @param int    $lockVersion
+     * @param object                     $entity
+     * @param int                        $lockMode
+     * @param int|DateTimeInterface|null $lockVersion
      *
      * @return void
      *
@@ -2494,7 +2495,11 @@ public function lock($entity, $lockMode, $lockVersion = null)
 
                 $entityVersion = $class->reflFields[$class->versionField]->getValue($entity);
 
-                if ($entityVersion !== $lockVersion) {
+                if ($entityVersion instanceof DateTimeInterface && $lockVersion instanceof DateTimeInterface) {
+                    if ($entityVersion->getTimestamp() !== $lockVersion->getTimestamp()) {
+                        throw OptimisticLockException::lockFailedVersionMismatch($entity, $lockVersion, $entityVersion);
+                    }
+                } elseif ($entityVersion !== $lockVersion) {
                     throw OptimisticLockException::lockFailedVersionMismatch($entity, $lockVersion, $entityVersion);
                 }
 
diff --git a/tests/Doctrine/Tests/ORM/Functional/Ticket/GH8499Test.php b/tests/Doctrine/Tests/ORM/Functional/Ticket/GH8499Test.php
new file mode 100644
index 00000000000..a18cb99890a
--- /dev/null
+++ b/tests/Doctrine/Tests/ORM/Functional/Ticket/GH8499Test.php
@@ -0,0 +1,166 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use DateTime;
+use DateTimeInterface;
+use Doctrine\DBAL\Connection;
+use Doctrine\DBAL\LockMode;
+use Doctrine\ORM\Mapping\Column;
+use Doctrine\ORM\Mapping\Entity;
+use Doctrine\ORM\Mapping\GeneratedValue;
+use Doctrine\ORM\Mapping\Id;
+use Doctrine\ORM\Mapping\Table;
+use Doctrine\ORM\Mapping\Version;
+use Doctrine\ORM\OptimisticLockException;
+use Doctrine\Tests\OrmFunctionalTestCase;
+use Exception;
+
+use function date;
+use function strtotime;
+
+class GH8499Test extends OrmFunctionalTestCase
+{
+    /** @var Connection */
+    protected $conn;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        try {
+            $this->_schemaTool->createSchema(
+                [$this->_em->getClassMetadata(GH8499VersionableEntity::class)]
+            );
+        } catch (Exception $e) {
+            // Swallow all exceptions. We do not test the schema tool here.
+        }
+
+        $this->conn = $this->_em->getConnection();
+    }
+
+    /**
+     * @group GH-8499
+     */
+    public function testOptimisticTimestampSetsDefaultValue(): GH8499VersionableEntity
+    {
+        $entity = new GH8499VersionableEntity();
+        $entity->setName('Test Entity');
+        $entity->setDescription('Entity to test optimistic lock fix with DateTimeInterface objects');
+        self::assertNull($entity->getRevision(), 'Pre-Condition');
+
+        $this->_em->persist($entity);
+        $this->_em->flush();
+
+        self::assertInstanceOf(DateTimeInterface::class, $entity->getRevision());
+
+        return $entity;
+    }
+
+    /**
+     * @group GH-8499
+     * @depends testOptimisticTimestampSetsDefaultValue
+     */
+    public function testOptimisticLockWithDateTimeForVersion(GH8499VersionableEntity $entity): void
+    {
+        $q = $this->_em->createQuery('SELECT t FROM Doctrine\Tests\ORM\Functional\Ticket\GH8499VersionableEntity t WHERE t.id = :id');
+        $q->setParameter('id', $entity->id);
+        $test = $q->getSingleResult();
+
+        $format       = $this->_em->getConnection()->getDatabasePlatform()->getDateTimeFormatString();
+        $modifiedDate = new DateTime(date($format, strtotime($test->getRevision()->format($format)) - 3600));
+
+        $this->conn->executeQuery('UPDATE GH8499VersionableEntity SET revision = ? WHERE id = ?', [$modifiedDate->format($format), $test->id]);
+
+        $this->_em->refresh($test);
+        $this->_em->lock($test, LockMode::OPTIMISTIC, $modifiedDate);
+
+        $test->setName('Test Entity Locked');
+        $this->_em->persist($test);
+        $this->_em->flush();
+
+        self::assertEquals('Test Entity Locked', $test->getName(), 'Entity not modified after persist/flush,');
+        self::assertGreaterThan($modifiedDate->getTimestamp(), $test->getRevision()->getTimestamp(), 'Current version timestamp is not greater than previous one.');
+    }
+
+    /**
+     * @group GH-8499
+     */
+    public function testOptimisticLockWithDateTimeForVersionThrowsException(): void
+    {
+        $entity = new GH8499VersionableEntity();
+        $entity->setName('Test Entity');
+        $entity->setDescription('Entity to test optimistic lock fix with DateTimeInterface objects');
+        $this->_em->persist($entity);
+        $this->_em->flush();
+
+        $this->expectException(OptimisticLockException::class);
+        $this->_em->lock($entity, LockMode::OPTIMISTIC, new DateTime('2020-07-15 18:04:00'));
+    }
+}
+
+/**
+ * @Entity
+ * @Table
+ */
+class GH8499VersionableEntity
+{
+    /**
+     * @Id
+     * @Column(type="integer")
+     * @GeneratedValue
+     * @var int
+     */
+    public $id;
+
+    /**
+     * @Column(type="string")
+     * @var string
+     */
+    public $name;
+
+    /**
+     * @Column(type="string")
+     * @var string
+     */
+    public $description;
+
+    /**
+     * @Version
+     * @Column(type="datetime")
+     * @var DateTimeInterface
+     */
+    public $revision;
+
+    public function getId(): int
+    {
+        return $this->id;
+    }
+
+    public function getName(): string
+    {
+        return $this->name;
+    }
+
+    public function setName(string $name): void
+    {
+        $this->name = $name;
+    }
+
+    public function getDescription(): string
+    {
+        return $this->description;
+    }
+
+    public function setDescription(string $description): void
+    {
+        $this->description = $description;
+    }
+
+    public function getRevision(): ?DateTimeInterface
+    {
+        return $this->revision;
+    }
+}