diff --git a/src/Symfony/Component/BrowserKit/Cookie.php b/src/Symfony/Component/BrowserKit/Cookie.php
index 672c98c5f3..6efef3f1d8 100644
--- a/src/Symfony/Component/BrowserKit/Cookie.php
+++ b/src/Symfony/Component/BrowserKit/Cookie.php
@@ -110,7 +110,7 @@ class Cookie
         }
 
         if (null !== $this->samesite) {
-            $str .= '; samesite='.$this->samesite;
+            $cookie .= '; samesite='.$this->samesite;
         }
 
         return $cookie;
diff --git a/src/Symfony/Component/BrowserKit/Tests/CookieTest.php b/src/Symfony/Component/BrowserKit/Tests/CookieTest.php
index 8dac3e14b5..41628b7014 100644
--- a/src/Symfony/Component/BrowserKit/Tests/CookieTest.php
+++ b/src/Symfony/Component/BrowserKit/Tests/CookieTest.php
@@ -29,6 +29,9 @@ class CookieTest extends TestCase
 
         $cookie = new Cookie('foo', 'bar', 0, '/', '');
         $this->assertEquals('foo=bar; expires=Thu, 01 Jan 1970 00:00:00 GMT; path=/; httponly', (string) $cookie);
+
+        $cookie = new Cookie('foo', 'bar', 2, '/', '', true, true, false, 'lax');
+        $this->assertEquals('foo=bar; expires=Thu, 01 Jan 1970 00:00:02 GMT; path=/; secure; httponly; samesite=lax', (string) $cookie);
     }
 
     /**