See Katy Perry, Rebecca Black's Acoustic "Friday" Performance
Once they finished their duet, Perry gave Black a hug and told the crowd: "Thank you so much, Rebecca. That was our moment. We love you Rebecca! Give it up!"
Black recently made a cameo in Perry's "Last Friday Night (T.G.I.F.)" music video. Still riding high on the success of "Friday" (and her current single, "My Moment), Black also picked up a surfboard for Choice Web Star at Sunday's Teen Choice Awards in Universal City, Calif.