Post Malone was joined by drummer Chad Smith (Red Hot Chili Peppers) and guitarist Slash (Guns n’ Roses) during his performance on Thursday (December 31) as part of “Bud Light Seltzer Sessions Presents: New Years Eve 2021” livestream. The rapper performed a cover of Alice In Chains’ “Rooster” with Smith, guitarist/producer Andrew Watt and bassist Chris Chaney, before playing Black Sabbath’s classic “War Pigs” with the help of Slash and the aforementioned musicians.