diff --git a/apex/prebuilt.go b/apex/prebuilt.go
index 6fdd50a..14020fc 100644
--- a/apex/prebuilt.go
+++ b/apex/prebuilt.go
@@ -915,6 +915,15 @@
 	return false
 }
 
+func (a *ApexSet) OutputFiles(tag string) (android.Paths, error) {
+	switch tag {
+	case "":
+		return android.Paths{a.outputApex}, nil
+	default:
+		return nil, fmt.Errorf("unsupported module reference tag %q", tag)
+	}
+}
+
 // prebuilt_apex imports an `.apex` file into the build graph as if it was built with apex.
 func apexSetFactory() android.Module {
 	module := &ApexSet{}