Last night at the iHeart Radio Music Festival, Katy Perry brought out a special guest in Juicy J. Together, the two performed "Dark Horse," their recent collaboration. As Juicy starts performing his verse on the song, Perry struts around and dances, clearing getting into the mood of the song. While the collaboration is unexpected, the two clearly have good chemistry with each other.

"Dark Horse" will appear on Perry's upcoming album Prism, slated for a October 22 release.

[via HHNM]

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