Crosby, Sinatra, Jolson all now deceased, Belafonte, Seeger, Joan Baez. Pavorati, among the living, 2 real superstars not singers or musicians would be The Pope and Billy Graham. If the audience are real fans of one particular type of music/show then any "NAME" doing that kind of music should be able to hold that size of an audience. The secret would be his/her patter between the numbers. A good showman/woman would have no problem but just to sing one song after another without any interaction between the performer and the audience couild prove difficult for all but the superstars.