Jack U is Skrillex & Diplo. Live set from Ultra Music Festival on March 30, 2014. . Jack Ü closing Ultra Music Festival Miami 2015 with guest appearances of Kiesza, Justin Bieber and Diddy. March 29th, 2015 - Bayfront Park, Downtown Miami. Skrillex & special guests live at Ultra Music Festival 2015 . DOWNLOAD this set here: For MORE LIVESETS, TRACKS & DOWNLOADS, visit us at: LIKE .