Crystal Castles is a Toronto, Ontario, Canada based duo consisting of multi-instrumentalist Ethan Kath and vocalist Alice Glass. Named after the Crystal Castle from the She-Ra franchise, they formed in December 2003 as a project started by Kath. In April 2005, Glass recorded vocals for five original instrumentals by Kath. The band’s first single was recorded “accidentally”: a microphone test by Glass was released through MySpace as "Alice Practice" in September 2005. Glass was not aware that it had been used until record companies heard the song and contacted the duo to offer them record deals. Crystal Castles are known not only for their own efforts as a band, but also for commissioned remixes for number of groups, including "Hunting for Witches" by Bloc Party, and "Atlantis to Interzone" by friends and label mates, Klaxons.

With eccentricity and originality at the heart of their music, Health don’t disappoint. Broadly classed as noise rock, the four-piece defy pinpoint definition and enjoy mixing it up with varied collaborations, with, amongst others, their good friends Crystal Castles.