diff --git a/src/LiveComponent/src/DependencyInjection/Compiler/ComponentDefaultActionPass.php b/src/LiveComponent/src/DependencyInjection/Compiler/ComponentDefaultActionPass.php
index a4327b7fe73..7b7af14d479 100644
--- a/src/LiveComponent/src/DependencyInjection/Compiler/ComponentDefaultActionPass.php
+++ b/src/LiveComponent/src/DependencyInjection/Compiler/ComponentDefaultActionPass.php
@@ -25,11 +25,15 @@ final class ComponentDefaultActionPass implements CompilerPassInterface
 {
     public function process(ContainerBuilder $container): void
     {
-        foreach ($container->findTaggedServiceIds('twig.component') as $class => $component) {
+        foreach ($container->findTaggedServiceIds('twig.component') as $id => $component) {
             if (!($component[0]['live'] ?? false)) {
                 continue;
             }
 
+            if (!$class = $container->getDefinition($id)->getClass()) {
+                throw new \LogicException(sprintf('Live component service "%s" must have a class.', $id));
+            }
+
             $defaultAction = trim($component[0]['default_action'] ?? '__invoke', '()');
 
             if (!method_exists($class, $defaultAction)) {
diff --git a/src/LiveComponent/tests/Fixtures/Kernel.php b/src/LiveComponent/tests/Fixtures/Kernel.php
index a7bead14e0d..ff8f408cfce 100644
--- a/src/LiveComponent/tests/Fixtures/Kernel.php
+++ b/src/LiveComponent/tests/Fixtures/Kernel.php
@@ -24,6 +24,7 @@
 use Symfony\Component\HttpKernel\Kernel as BaseKernel;
 use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;
 use Symfony\UX\LiveComponent\LiveComponentBundle;
+use Symfony\UX\LiveComponent\Tests\Fixtures\Component\Component1;
 use Symfony\UX\LiveComponent\Tests\Fixtures\Serializer\Entity2Normalizer;
 use Symfony\UX\LiveComponent\Tests\Fixtures\Serializer\MoneyNormalizer;
 use Symfony\UX\TwigComponent\TwigComponentBundle;
@@ -129,7 +130,10 @@ protected function configureContainer(ContainerConfigurator $c): void
             ->set(Entity2Normalizer::class)->autoconfigure()->autowire()
             ->load(__NAMESPACE__.'\\Component\\', __DIR__.'/Component')
             ->set(TestingDeterministicIdTwigExtension::class)
-            ->args([service('ux.live_component.deterministic_id_calculator')]);
+            ->args([service('ux.live_component.deterministic_id_calculator')])
+            ->set('some_service_id', Component1::class)
+                ->tag('twig.component', ['live' => true])
+        ;
     }
 
     protected function configureRoutes(RoutingConfigurator $routes): void