Amy Winehouse, Razorlight and Leona Lewis are among tonight's line-up for Nelson Mandela's 90th birthday celebrations in Hyde Park.
The concert will also star several performers who sang at a rally to free the South African statesman from prison, held 20 years ago.
Jerry Dammers, whose song Free Nelson Mandela became synonymous with the anti-apartheid movement in Britain in the 1980s, will take the stage along with Simple Minds and Annie Lennox, who were also at the 1988 concert.
There were concerns that Winehouse would not take part in the concert after doctors diagnosed early signs of lung condition emphysema, but she is said to be rehearsing the song Free Nelson Mandela for the concert.
Queen is also taking part, as are the Sugababes, the Soweto gospel choir and Eddy Grant.
Proceeds from the show, which is hosted by Will Smith, will go to 46664, the AIDS charity named for the number Mandela wore in prison.
Although Mandela retired from politics nine years ago, he is still seen as a moral authority.
He recently chose to speak out against Zimbabwe's president Robert Mugabe, saying the situation was a "tragic failure of leadership", making headlines around the world.
Nelson Mandela was imprisoned by the South African government for 27 years for his stand against apartheid. He was released in 1990 and became the country's first black president in 1994.