The Boss with Elton John. Shirley Bassey, Lady Gaga, Sting and Blondie doing Journey's Don't Stop Believin.

Lady Gaga, Springsteen and Friends Stage The Greatest Karaoke Session Ever - Stop The Presses! (http://new.music.yahoo.com/blogs/stopthepresses/198222/lady-gaga-springsteen-and-friends-stage-the-greatest-karaoke-session-ever/)