Butterscotch performed with the guy who sings Beautiful Girls (a song that I can't stand and that seems to follow me everywhere) Sean Kingston. Julienne Irwin performed with the country singer whose name escapes me right now - umm she's 17yrs old and one best new female vocalist this year from what they said on the show. Hope that helps. Cas Haley performed with UB40. Oh, and here's a link to an after the show interview that he talks about performing with Kermit and seeing the muppets there: http://www.nbc.com/Americas_Got_Talent/video/#mea=146370 The comments about that are located at the point where there is 1:20 left of the video to play. It is so refreshing to see his honesty about having been able to have the opportunity.