diff --git a/api/fields/file_fields.py b/api/fields/file_fields.py
index a6e2d7038b..c12ebc09c8 100644
--- a/api/fields/file_fields.py
+++ b/api/fields/file_fields.py
@@ -32,7 +32,8 @@ file_fields = {
     "mime_type": fields.String,
     "created_by": fields.String,
     "created_at": TimestampField,
-    "preview_url": fields.String(attribute="source_url"),
+    "preview_url": fields.String,
+    "source_url": fields.String,
 }