Wondering where Jon Hamm has been since Mad Men wrapped? He joined Zach Galifianakis to kick off the star-packed '80s throwback-themed SuperJam at Bonnaroo on Saturday. The last time we saw Don Draper, he was decked out in hippie boho chic, chanting and smiling to himself about his big Coke idea. Now, we get to see what Don would have been like as an 80s fan of slow jams. Hamm and Galifianakis sang "We Are the World" to a pumped crowd. Hamm and Galifianakis surprised many in the crowd, and had been surprising crowds all day: They appeared unannounced at the Comedy Club (Hamm fed Galifianakis gummy bears (surely a recreation of someone's fantasy). Hamm then fed Belle and Sebastian gummy bears during their set, according to Stereogum. The SuperJam continued with Jack Antonoff, DMC (Run-DMC), Rob Trujillo (of Metallica), Rhiannon Giddens, Chance the Rapper, and more, covering a decade of songs for an audience who — presumably — didn't actually exist in that decade since nearly half of 'roo attendees are under 24. The party went well into the early morning hours, as hoards of Bonnaroovians danced under a light show to the music.