diff --git a/src/Symfony/Bundle/Test/Client.php b/src/Symfony/Bundle/Test/Client.php
index b6192abd70..1936314ab5 100644
--- a/src/Symfony/Bundle/Test/Client.php
+++ b/src/Symfony/Bundle/Test/Client.php
@@ -236,6 +236,8 @@ private static function extractHeaders(array $options): array
 
     public function loginUser(UserInterface $user, string $firewallContext = 'main'): self
     {
+        $this->kernelBrowser->getKernel()->boot();
+
         $this->kernelBrowser->loginUser($user, $firewallContext);
 
         return $this;