Former South Africa’s President Nelson Mandela is celebrating 94th birthday on Wednesday and some 12 million schoolchildren across the country have sung a specially composed song as part of official celebrations.

Nelson Mandela will spend the day quietly with his family in his village home of Qunu in the Eastern Cape, near where he was born.

The former president met former US President Bill Clinton on Tuesday.

Nelson Mandela spent 27 years in jail for leading an armed anti-apartheid campaign.

Nelson Mandela met former US President Bill Clinton one day before his 94th birthday

Bill Clinton, accompanied by his daughter Chelsea, opened a new library for the No-Moscow Primary School in Qunu, ahead of his meeting with Nelson Mandela.

He told the children that Madiba – as Nelson Mandela is affectionately called in South Africa – believed in the future and not the past.

“When I think about Mandela I always think about someone committed to the future,” Bill Clinton said.

US President Barack Obama and his wife, Michelle Obama, have also paid tribute ahead of Nelson Mandela’s birthday.

The US first couple hailed Neslon Mandela’s “extraordinary life and steadfast commitment to the principles of democracy and reconciliation.”

Nelson Mandela’s birthday is traditionally celebrated with the poor communities receiving help from those who are more fortunate.

To celebrate the number of years Nelson Mandela spent in public life, people are encouraged to spend at least 67 minutes of their time helping those who are less fortunate.

The guest list for a private lunch with Nelson Mandela has, however, been kept a closely guarded secret.