Katy Perry and Juicy J come together on the music song Dark Horse from off Katy Perry's album Prism.
Described as a "Southern rap-techno mashup," the song "Dark Horse" started to form in Perry's hometown of Santa Barbara, California during a writing session with Perry and Hudson.
Juicy J was then invited to join Katy Perry on Dark Horse by the song's producer Dr. Luke, after Perry requested Luke contact Juicy J.
The rest was magic; the song "Dark Horse" has been a success reaching number 1 on the US Billboard Hot 100.
Listen to "Dark Horse" by Katy Perry featuring Juicy J: