Acts announced for Nelson Mandela tribute concert

Leona Lewis has been lined up to play at a star-studded 90th birthday concert for Nelson Mandela.

The London-born singer will join the bill along with Amy Winehouse, Duffy, Razorlight, Keane and Sugababes.

45,000 tickets will be made available for the 27 June 2008 event which will take place in London's Hyde Park.