Justin Bieber loves making surprise cameos at music festivals!
On Sunday, the singer surprised audiences when he came out on stage during Jack U‘s set at the Hard Summer Music Festival in Pomona, California!
The 21-year-old rocked a grungy Metallica T-shirt as he hit the stage with Diplo and Skrillex –when the four artists performed their hit collaboration Where Are U Now!
Check out the footage (below) to see the crowd go wild for Bieberoni & co.’s performance:
[Image via WENN.]