At Ultra Music Festival this past March (2015), Jack U‘s set saw a surprise special guest appearance from Justin Bieber to close out their set, as he joined Skrillex and Diplo on the main stage to perform their collaboration, “Where Are U Now.” Amongst the Electric Daisy Carnival celebrations in Las Vegas this past weekend, Kaskade performed at XS Las Vegas, where he would be joined by Bieber while performing his remix of the popular Jack U collaboration with the pop superstar. In the video above, you can see several angles of Bieber's guest appearance. The Kaskade remix is now available as part of the official “Where Are U Now” remixes, which also contains reworks by Rustie, Marshmello and Ember Island. Grab the EP now on iTunes via OWSLA / Mad Decent / Atlantic.