Bill Clinton visits Mandela's village

"It was a great honour for me to serve as a president of America while Mandela was president of the Republic of South Africa," Clinton said.

He opened a library at a primary school together with Mandela's wife, Graca Machel, and daughter Zindzi ahead of the 1iconic leader's birthday tomorrow.

Around 3,000 schoolchildren, residents and government officials attended the library opening.

In 2009 the United Nations declared July 18 as International Mandela Day, aimed at getting people all over the world to volunteer for good causes.

Dozens of journalists and others have camped outside Mandela's home hoping to get a glimpse of the iconic leader. Millions of others have prepared to sing a special birthday song for him at tomorrow morning.

Thousands of South Africans will also engage in various community projects as they rally to the call to do something to better the lives of their fellowmen by donating 67 minutes of their time.

The 67 figure comes from the number of years that Mandela fought for freedom before leading South Africa to its first democratic elections in 1994 that made him president. Mandela spent 27 of those years in prison.

Mandela was surrounded by four generations of his family as they celebrated his birthday privately.

He gave up making public appearances several years ago and rarely entertains visitors these days as well.

Earlier today, the Nelson Mandela Centre of Memory dismissed suggestions that Mandela's name was being exploited for commercial gain.

"We have developed an ethical framework that was negotiated with a whole range of partners which expressly asks that Nelson Mandela and Mandela Day is not commercialized. All we can do is set the example and ask other people to follow," said the Centre's chief executive Achmat Dangor.

Dangor said the intention with the annual 67 minutes campaign, started when Mandela turned 90, has always been to celebrate his legacy through community service.