Post Malone was part of last night's Bud Light New Year's Eve celebration and he brought along some friends, including producer Andrew Watt (who is working on the new Ozzy album) and Guns N Roses guitarist Slash and Red Hot Chili Peppers drummer Chad Smith. Two of the songs performed were covers of heavy metal classics "War Pigs" by Black Sabbath and Alice In Chains' "Rooster." (Slash was present for the Sabbath cover)