Sources said that others who have been approached include the Spice Girls, U2, Paul McCartney and rapper Eminem.
While Eminem, U2 and the aforementioned artists possibly performing have not been confirmed, a source said that since it will most likely be Mandela's "last official international public appearance," they want it to be "special."
The source also told The Sun that "Eminem's up for it too. People will be surprised. He's not someone you'd expect to play a Mandela charity gig."
http://www.ballerstatus.com/article/news/2008/03/4224/