diff --git a/src/borg/platform/freebsd.pyx b/src/borg/platform/freebsd.pyx
index c38f03588..3eabe6267 100644
--- a/src/borg/platform/freebsd.pyx
+++ b/src/borg/platform/freebsd.pyx
@@ -200,7 +200,7 @@ cdef _nfs4_use_stored_uid_gid(acl):
         if entry:
             if entry.startswith('user:') or entry.startswith('group:'):
                 fields = entry.split(':')
-                entries.append(':'.join(fields[0], fields[5], *fields[2:-1]))
+                entries.append(':'.join([fields[0], fields[5]] + fields[2:-1]))
             else:
                 entries.append(entry)
     return safe_encode('\n'.join(entries))