"Dark Horse" is a song by American singer Katy Perry featuring American rapper Juicy J. It was originally released on September 17, 2013, by Capitol Records as the first promotional single from Perry's fourth studio album, Prism (2013). Three months later, it was released as the third official single on December 17. Both artists co-wrote the song with its producers, Max Martin, Cirkut, and Dr. Luke, alongside Sarah Hudson. It was conceived by Perry and Hudson during a writing session in Perry's hometown of Santa Barbara, California, and Juicy J was later commissioned for a verse on the song.

Katheryn Elizabeth Hudson, known professionally as Katy Perry, is an American singer, songwriter, and television personality. She is known for her influence on modern pop music and her camp style, being dubbed the "Queen of Camp" by Vogue and Rolling Stone. At 16, Perry released a gospel record titled Katy Hudson (2001) under Red Hill Records, which was commercially unsuccessful. She moved to Los Angeles at 17 to venture into secular music, and later adopted the stage name "Katy Perry" from her mother's maiden name. She recorded an album while signed to Columbia Records, but was dropped before signing to Capitol Records.