Who knew Selena Gomez and Skrillex were pals? The 'Who Says' singer partied with the dubstep king and his girlfriend, Ellie Goulding, as well as with her 'Spring Breakers' costar Ashley Benson.

Incognito in a bright red wig and black mask, Gomez joined Benson, who sported pink tips on her blond locks, at the Ultra Music Festival in Miami. The girls were nearby filming 'Spring Breakers,' in which they don bikinis and get into a whole mess of trouble. (Gomez even gets arrested!)

Skrillex was one of the headlining DJs for the festival, which also boasted sets from David Guetta and Avicii -- who was joined by none other than Madonna.

Skrillex and Ellie Goulding have been a cute couple since November 2011. The Los Angeles-based DJ and the U.K. chanteuse have kept their romance pretty low on the radar, though reports surfaced that they met through mutual colleagues and kept in touch over email. This is one of the few times they've been photographed together. They look so happy!