See Katy Perry, Rebecca Black's Acoustic "Friday" Performance

See Katy Perry, Rebecca Black's Acoustic "Friday" Performance

YouTube sensation Rebecca Black, 14, joined her mentor Katy Perry, 26, for an acoustic performance of "Friday" in L.A. over the weekend.

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.