diff --git a/src/borg/archiver/tar_cmds.py b/src/borg/archiver/tar_cmds.py
index 2ee5a0712..c273ffde7 100644
--- a/src/borg/archiver/tar_cmds.py
+++ b/src/borg/archiver/tar_cmds.py
@@ -132,8 +132,8 @@ def item_to_tarinfo(item, original_path):
             tarinfo.name = item.path
             tarinfo.mtime = item.mtime / 1e9
             tarinfo.mode = stat.S_IMODE(item.mode)
-            tarinfo.uid = item.uid
-            tarinfo.gid = item.gid
+            tarinfo.uid = item.get("uid", 0)
+            tarinfo.gid = item.get("gid", 0)
             tarinfo.uname = item.get("user", "")
             tarinfo.gname = item.get("group", "")
             # The linkname in tar has 2 uses: