diff --git a/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php b/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
index fb69d9c..df23e76 100644
--- a/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
+++ b/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
@@ -371,7 +371,9 @@ public static function process($element, FormStateInterface $form_state, $form)
     $item = $element['#value'];
     $item['fids'] = $element['fids']['#value'];
 
-    $element['#theme'] = 'file_widget';
+    if (!isset($element['#theme'])) {
+      $element['#theme'] = 'file_widget';
+    }
 
     // Add the display field if enabled.
     if ($element['#display_field']) {