diff --git a/src/DependencyInjection/TracyBlueScreenExtension.php b/src/DependencyInjection/TracyBlueScreenExtension.php
index 45dcfe8..ad35220 100644
--- a/src/DependencyInjection/TracyBlueScreenExtension.php
+++ b/src/DependencyInjection/TracyBlueScreenExtension.php
@@ -26,7 +26,7 @@ final class TracyBlueScreenExtension extends ConfigurableExtension implements Pr
     public const CONTAINER_PARAMETER_CONSOLE_LISTENER_PRIORITY = 'cdn77.tracy_blue_screen.console.listener_priority';
     public const CONTAINER_PARAMETER_CONSOLE_LOG_DIRECTORY = 'cdn77.tracy_blue_screen.console.log_directory';
     public const CONTAINER_PARAMETER_CONTROLLER_LISTENER_PRIORITY = 'cdn77.tracy_blue_screen.controller.listener_priority';
-    private const TWIG_BUNDLE_ALIAS = 'twig';
+    public const TWIG_BUNDLE_ALIAS = 'twig';
     private const TWIG_TEMPLATES_NAMESPACE = 'Twig';
 
     public function prepend(ContainerBuilder $container) : void
diff --git a/src/TracyBlueScreenBundle.php b/src/TracyBlueScreenBundle.php
index 14181bd..a0444a6 100644
--- a/src/TracyBlueScreenBundle.php
+++ b/src/TracyBlueScreenBundle.php
@@ -4,8 +4,16 @@
 
 namespace Cdn77\TracyBlueScreenBundle;
 
+use Symfony\Bundle\TwigBundle\DependencyInjection\TwigExtension;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\HttpKernel\Bundle\Bundle;
 
 final class TracyBlueScreenBundle extends Bundle
 {
+    public function build(ContainerBuilder $container) : void
+    {
+        parent::build($container);
+
+        $container->registerExtension(new TwigExtension());
+    }
 }
diff --git a/tests/Cdn77/TracyBlueScreenBundle/TracyBlueScreenBundleTest.php b/tests/Cdn77/TracyBlueScreenBundle/TracyBlueScreenBundleTest.php
new file mode 100644
index 0000000..eb2ae73
--- /dev/null
+++ b/tests/Cdn77/TracyBlueScreenBundle/TracyBlueScreenBundleTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cdn77\TracyBlueScreenBundle;
+
+use Cdn77\TracyBlueScreenBundle\DependencyInjection\TracyBlueScreenExtension;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+
+final class TracyBlueScreenBundleTest extends TestCase
+{
+    public function testRegistersTwig() : void
+    {
+        $containerBuilder = new ContainerBuilder();
+        $bundle = new TracyBlueScreenBundle();
+        $bundle->build($containerBuilder);
+
+        self::assertTrue($containerBuilder->hasExtension(TracyBlueScreenExtension::TWIG_BUNDLE_ALIAS));
+    }
+}