diff --git a/src/Symfony/Component/Routing/Router.php b/src/Symfony/Component/Routing/Router.php
index 5f8d9ffb159d..c4fb3e2151bd 100644
--- a/src/Symfony/Component/Routing/Router.php
+++ b/src/Symfony/Component/Routing/Router.php
@@ -369,7 +369,7 @@ function (ConfigCacheInterface $cache) {
             );
 
             if ($compiled) {
-                $this->generator = new $this->options['generator_class'](require $cache->getPath(), $this->context, $this->logger);
+                $this->generator = new $this->options['generator_class'](require $cache->getPath(), $this->context, $this->logger, $this->defaultLocale);
             } else {
                 if (!class_exists($this->options['generator_cache_class'], false)) {
                     require_once $cache->getPath();
diff --git a/src/Symfony/Component/Routing/Tests/RouterTest.php b/src/Symfony/Component/Routing/Tests/RouterTest.php
index fa0a2f5399ac..0d7c4bee456c 100644
--- a/src/Symfony/Component/Routing/Tests/RouterTest.php
+++ b/src/Symfony/Component/Routing/Tests/RouterTest.php
@@ -22,10 +22,26 @@ class RouterTest extends TestCase
 
     private $loader = null;
 
+    private $cacheDir;
+
     protected function setUp(): void
     {
         $this->loader = $this->getMockBuilder('Symfony\Component\Config\Loader\LoaderInterface')->getMock();
         $this->router = new Router($this->loader, 'routing.yml');
+
+        $this->cacheDir = sys_get_temp_dir().\DIRECTORY_SEPARATOR.uniqid('router_', true);
+    }
+
+    protected function tearDown(): void
+    {
+        if (is_dir($this->cacheDir)) {
+            array_map('unlink', glob($this->cacheDir.\DIRECTORY_SEPARATOR.'*'));
+            rmdir($this->cacheDir);
+        }
+
+        $this->loader = null;
+        $this->router = null;
+        $this->cacheDir = null;
     }
 
     public function testSetOptionsWithSupportedOptions()
@@ -132,4 +148,68 @@ public function testMatchRequestWithRequestMatcherInterface()
 
         $this->router->matchRequest(Request::create('/'));
     }
+
+    public function testDefaultLocaleIsPassedToGeneratorClass()
+    {
+        $this->loader->expects($this->once())
+            ->method('load')->with('routing.yml', null)
+            ->willReturn(new RouteCollection());
+
+        $router = new Router($this->loader, 'routing.yml', [
+            'cache_dir' => null,
+        ], null, null, 'hr');
+
+        $generator = $router->getGenerator();
+
+        $this->assertInstanceOf('Symfony\Component\Routing\Generator\UrlGeneratorInterface', $generator);
+
+        $p = new \ReflectionProperty($generator, 'defaultLocale');
+        $p->setAccessible(true);
+
+        $this->assertSame('hr', $p->getValue($generator));
+    }
+
+    public function testDefaultLocaleIsPassedToCompiledGeneratorCacheClass()
+    {
+        $this->loader->expects($this->once())
+            ->method('load')->with('routing.yml', null)
+            ->willReturn(new RouteCollection());
+
+        $router = new Router($this->loader, 'routing.yml', [
+            'cache_dir' => $this->cacheDir,
+        ], null, null, 'hr');
+
+        $generator = $router->getGenerator();
+
+        $this->assertInstanceOf('Symfony\Component\Routing\Generator\UrlGeneratorInterface', $generator);
+
+        $p = new \ReflectionProperty($generator, 'defaultLocale');
+        $p->setAccessible(true);
+
+        $this->assertSame('hr', $p->getValue($generator));
+    }
+
+    /**
+     * @group legacy
+     */
+    public function testDefaultLocaleIsPassedToNotCompiledGeneratorCacheClass()
+    {
+        $this->loader->expects($this->once())
+            ->method('load')->with('routing.yml', null)
+            ->willReturn(new RouteCollection());
+
+        $router = new Router($this->loader, 'routing.yml', [
+            'cache_dir' => $this->cacheDir,
+            'generator_class' => 'Symfony\Component\Routing\Generator\UrlGenerator',
+        ], null, null, 'hr');
+
+        $generator = $router->getGenerator();
+
+        $this->assertInstanceOf('Symfony\Component\Routing\Generator\UrlGeneratorInterface', $generator);
+
+        $p = new \ReflectionProperty($generator, 'defaultLocale');
+        $p->setAccessible(true);
+
+        $this->assertSame('hr', $p->getValue($generator));
+    }
 }