Jack Ü was an American electronic dance music duo consisting of electronic music producers Skrillex and Diplo, formed in 2013. They released their first official single, "Take Ü There", featuring vocals from Kiesza, on October 4, 2014. They released their first and only album, Skrillex and Diplo Present Jack Ü, on February 27, 2015.

Jack Ü performed at Ultra Music Festival Miami in 2014. They also performed at Ultra Music Festival in 2015 with the entire "Jack Ü crew", featuring live contributions from CL, Kai, Diddy, Kiesza and Justin Bieber.

According to Skrillex, the collaboration is called 'Jack Ü' because it refers to how the music "jacks you up" with its high energy beats and bassline. The Ü (U with umlaut) letter appears in titles of all of its singles and is usually stylized to look like a smiley.