"Where Are Ü Now" is a song produced by American EDM artists Skrillex and Diplo under their collaborative effort Jack Ü, with vocals from Canadian singer Justin Bieber. The song was released as the second single from the duo's debut studio album, Skrillex and Diplo Present Jack Ü (2015), on their respective labels Owsla and Mad Decent, and is also included on Bieber's fourth studio album Purpose (2015). It was released simultaneously with the album on February 27, 2015, later sent to mainstream radio on April 21, 2015.

Sonny John Moore, known professionally as Skrillex, is an American DJ and music producer. Growing up in Northeast Los Angeles and Northern California, he joined the post-hardcore band From First to Last as its lead vocalist in 2004, and recorded two studio albums with the band—Dear Diary, My Teen Angst Has a Bodycount (2004) and Heroine in (2006)—before leaving to pursue a solo career in 2007. He began his first tour as a solo artist in late 2007. After recruiting a new band lineup, Moore joined the Alternative Press Tour to support bands such as All Time Low and the Rocket Summer, and appeared on the cover of Alternative Press's annual "100 Bands You Need to Know" issue.