![Katy Perry Duets With Rebecca Black in Concert – On Friday, Naturally [VIDEO]](http://townsquare.media/site/133/files/2011/08/KatePerryRebeccaBlack_edited-1.jpg?w=980&q=75)
Katy Perry Duets With Rebecca Black in Concert – On Friday, Naturally [VIDEO]
Pop diva Katy Perry had a surprise for those attending her Nokia Theater concert in LA last week: a duet with special guest Rebecca Black. It was a Friday night, of course.