CAPE TOWN (AFP) - Music stars from Bono to Beyonce responded to a call from South African elder statesman Nelson Mandela to sing at a gala concert to raise money against the scourge of HIV / AIDS.

Irish singer Bob Geldof told the 40,000 cheering and dancing fans in Cape Town, and hundreds of millions tuning in via radio, television and the Internet worldwide, that AIDS had a become a political issue for the world.

South Africa is the country in the world hardest hit by AIDS, with an estimated five million of its 45 million residents either infected with HIV or suffering from AIDS. After years of foot-dragging, the government earlier this month announced it would start to provide anti-retroviral drugs to tens of thousands from next year.

"It does not matter how much money or how little money the concert raises, AIDS is simply another medical condition," Geldof said.

"If the condition is medical, the solution is political. It is unacceptable that rich people can develop drugs, but the poor can not."

"AIDS lays to waste entire countries. It takes out factory workers, the teachers, the nurses, the doctors, the mothers, the fathers and the children, and the children and the children."

The organiser of the legendary Live Aid concerts for African famine victims in the 1980s said "we are here because... one of the giants of the planet summoned us here and you can not refuse him (Mandela) anything."

The crowds joined in an ecstatic sing-along as Geldof performed the slow-moving reggae tune "Redemption Song" by the late Jamaican singer Bob Marley.

Organisers said the event, beamed out from South Africa to TV, radio stations and the web had reached more than a billion people. Parts will be rebroadcast Monday, on World AIDS day.

American R and B singer Beyonce Knowles, who rose up from below the stage through a puff of smoke in a revealing multi-coloured dress, performed some her best known hits, including "Baby Boy" and "Dangerously in Love".

"My ladies, I want to tell all of you out there that there is nothing sexier than being confident and taking care of yourselves," Knowles told the crowd in a country where more than five million people are either HIV positive or have AIDS.

Bono, the frontman of the Irish band U2 introduced Mandela to the crowd.

"He is the president of everyone, everywhere who loves freedom," Bono shouted.

The beaming 85-year-old Mandela, who has become one of the world's most recognizable faces in the battle against AIDS, was given thunderous applause for several minutes, some of who held up a banner saying: "Mandela rocks".

"This concert is part of a vital campaign that is helping to end a tragedy of unprecedented proportions," Mandela said.

"It is claiming more lives than the sum total of all wars, famines and floods. AIDS is no longer a disease. It is a human rights issue."

The concert is part of Mandela's 46664 campaign -- the former statesman's prison number under apartheid -- which calls on all governments to declare a global AIDS emergency.

South African artists Johnny Clegg and the a capella group Ladysmith Black Mambazo were also warmly welcomed by the crowd.

Members of the audience cried as Clegg performed "Asimbonanga" in honour of Mandela.

Also performing were Youssou N'Dour from Senegal, Angelique Kidjo from Benin, Peter Gabriel, Brazilian-born singer Anastacia, Irish pop band The Corrs, the Eurythmics and Queen.

Some 6,500 people a day die from AIDS each day in Africa. The disease has so far killed 17 million people on the continent, while about 37 million Africans are infected with HIV, or have full-blown AIDS.

More than three million people have died from AIDS or AIDS-related illnesses so far this year, according to UNAIDS.