diff --git a/antlir/antlir2/bzl/package/defs.bzl b/antlir/antlir2/bzl/package/defs.bzl
index 21b487c855..ce5ce959f0 100644
--- a/antlir/antlir2/bzl/package/defs.bzl
+++ b/antlir/antlir2/bzl/package/defs.bzl
@@ -101,7 +101,7 @@ _package = rule(
 _package_macro = rule_with_default_target_platform(_package)
 
 def BtrfsSubvol(
-        layer: str.type,
+        layer: [str.type, "selector"],
         writable: [bool.type, None] = None):
     return {
         "layer": layer,