According to Led-Zeppelin.org, former LED ZEPPELIN singer Robert Plant makes a guest vocal appearance on BUDDY & JULIE MILLER's song "What You Gonna Do Leroy".
The track, which can be heard in the embedded video below, is available on the BUDDY & JULIE MILLER album "Written In Chalk".
Miller and Plant trade vocals on the track, sharing and trading off lines and verses. They are joined by fellow touring mates Jay Bellerose on drums, Dennis Crouch on bass, and Stuart Duncan on fiddle. Adding lap steel to the track is Gurf Morlix.