WireImage/Prince Williams

Justin Bieber And Diddy Crash Skrillex's Set At Ultra Music Festival

Bieber joins Skrill and Diplo for 'Where Are Ü Now.'

Justin Bieber is back!!

The singer took over Skrillex's set at Ultra Music Festival on Sunday night in Miami, and we were there to catch the magic.

After Diplo joined his Jack Ü partner at the main stage, they invited tons of guests to join them onstage, including Kiesza, CL, Diddy and JBiebs, who performed their song "Where Are Ü Now."

This is the second night in a row that Bieber has crashed someone else's set. Ariana Grande invited him to her Miami stop of the Honeymoon Tour last night. Ariana also made an appearance at Ultra on Sunday, preforming two songs with Cashmere Cat.