This is a promotional single for Tron: Legacy Soundtrack, the album for the 2010 film Tron: Legacy composed by French electronic duo Daft Punk. It was the first film score released by Daft Punk.
The score features an 85-piece orchestra, recorded at AIR Lyndhurst Studios in London. Thomas Bangalter of Daft Punk commented that, "We knew from the start that there was no way we were going to do this film score with two synthesizers and a drum machine."
The song's official music video was released online on December 7, 2010. The clip features Daft Punk playing an old arcade game in Kevin Flynn's arcade from the movie, plus an appearance by Tron: Legacy cast member Olivia Wilde.
Katy Perry's "Dark Horse" was co-written by Sarah Hudson, who is a singer-songwriter and a member of the Pop group Ultraviolet Sound. Though Sarah isn't related to Katy (whose real name is Katy Hudson), she is the first cousin of another famous person with the same name, the actress Kate Hudson.