Katy Perry and Juicy J hit up the iHeartRadio stage at the MGM Grand in Vegas to perform their “Dark Horse” song for the first time ever. The track is set to appear on Katy’s Prism album that’s hitting stores October 22nd. Of course Juicy was hyping up the crowd by yelling, “Turn Up.” Luckily for him, it worked! Check out the live performance of the Trippy rapper and Ms. Perry after the jump!

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