The Nelson Mandela Foundation announced on Monday that former US President Barack Obama will deliver the annual Nelson Mandela Lecture of the late South African Statesman at Ellis Park Stadium in Johannesburg.

"The Nelson Mandela Foundation is honoured to announce that President Barack Obama accepted our invitation to be the speaker at this year’s 16th Nelson Mandela Annual Lecture to take place in Johannesburg on 17 July, ahead of Madiba’s birthday," the Foundation's chief executive, Sello Hatang, said.

The announcement was made at the launch of Nelson Mandela Day which will also serve as a countdown to Mandela's centennial birthday on July 18.

The United Nations declared July 18 International Nelson Mandela Day. Annually, on this day, people across political divides in South Africa and other parts of the world devote 67 minutes doing charitable work. The 67 minutes signify the 67 years Madiba dedicated to the service of others.

Mandela would have turned 100 this year. The former president died in 2013 aged 95.