diff --git a/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php b/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php
index 0d23358..c41029b 100644
--- a/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php
+++ b/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php
@@ -192,7 +192,10 @@ protected function getEntityUri(EntityInterface $entity, array $context = []) {
       return $entity->url('canonical', []);
     }
     $url = $entity->urlInfo('canonical', ['absolute' => TRUE]);
-    $generated_url = $url->setRouteParameter('_format', 'hal_json')->toString(TRUE);
+    if (!$url->isExternal()) {
+      $url->setRouteParameter('_format', 'hal_json');
+    }
+    $generated_url = $url->toString(TRUE);
     $this->addCacheableDependency($context, $generated_url);
     return $generated_url->getGeneratedUrl();
   }