Mandela was speaking on Friday from the island prison where he was held for 18 years before white rule ended in 1994.
He was accompanied on the trip by Irish rock star Bono, American R&B sensation Beyonce and other singers due to perform at an Aids benefit concert in Cape Town on Saturday.
Mandela, whose country is one of the main venues for events marking World Aids Day on Monday, praised South Africa's recent decision to reverse years of policy and begin providing AIDS drugs to infected people.
"Our government announced policy measures that will once more put us in the lead to fight the epidemic. It is most fitting that this coming together happens so close on the heels of that groundbreaking announcement," Mandela said.
Mbeki has taken more
forceful steps to fight Aids
The 85-year-old Mandela, who stepped down as South Africa's first black president in 1999, has become one of the world's leading campaigners on Aids.
The disease has hit South Africa harder than any other country with more than five million of its 45 million people infected.
Bowing to widespread calls for a more aggressive approach to the epidemic, the South African government of President Thabo Mbeki this month finally unveiled a plan to begin bringing anti-retroviral drugs to the public sector.
Mandela said Saturday's concert - dubbed 46664 after his long-time prison number and due to be broadcast around the world by the music channel MTV - showed international solidarity could still be mustered to fight the world's biggest problems.
Yusuf Islam, once known as Cat
Stevens, performs on Saturday
"South Africans fought a noble struggle against the evils of apartheid ... today we find ourselves facing an even greater threat. It threatens our future on a scale that could not have been imagined," Mandela said.
"The artists here are a demonstration that international solidarity remains in the war against Aids."
The stars, who included British celebrities Annie Lennox, Peter Gabriel, members of Queen, and Yusuf Islam, who was formerly known as Cat Stevens, did not speak to reporters but later took a tour of Mandela's island prison cell.
Asked if he enjoyed the music that would be on offer, Mandela said he was still learning the ins-and-outs of modern popular culture.
"I enjoy music and whenever I get time I listen. I used to know all singles by Cesar Romero," Mandela said.
"The new ones are more difficult for me to identify, but whenever I do have a chance of listening, I enjoy listening."