diff --git a/src/Flysystem/S3.php b/src/Flysystem/S3.php
index f8a80a7..83dc8a9 100644
--- a/src/Flysystem/S3.php
+++ b/src/Flysystem/S3.php
@@ -8,6 +8,7 @@ use Aws\S3\S3Client;
 use Drupal\Component\Utility\UrlHelper;
 use Drupal\Core\Logger\RfcLogLevel;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\Core\Site\Settings;
 use Drupal\flysystem\Plugin\FlysystemPluginInterface;
 use Drupal\flysystem\Plugin\FlysystemUrlTrait;
 use Drupal\flysystem\Plugin\ImageStyleGenerationTrait;
@@ -75,7 +76,11 @@ class S3 implements FlysystemPluginInterface, ContainerFactoryPluginInterface {
     $this->prefix = $config->get('prefix', '');
     $this->options = $config->get('options', []);
 
-    $this->urlPrefix = $this->calculateUrlPrefix($config);
+    if ($file_public_base_url = Settings::get('file_public_base_url')) {
+      $this->urlPrefix = $file_public_base_url;
+    } else {
+      $this->urlPrefix = $this->calculateUrlPrefix($config);
+    }
   }
 
   /**