Volunteers will spend 67 minutes on hundreds of community upliftment projects — a minute for every year of the anti-apartheid hero's activism. This despite his hospitalisation and bitter infighting among his relatives.
The United Nations in 2010 declared the Nobel peace laureate's birthday Mandela Day — to encourage people around the world to do just over an hour of good deeds.
Global celebrities have supported the campaign in memory of Mandela's 67 years of political activism.
"I will also be giving my 67 minutes to make the world a better place, one small step at a time," British business magnate Richard Branson pledged.
On Thursday, children in schools around South Africa will start their classes singing "Happy Birthday" to the former statesman. Celebrities have committed to painting schools, handing out clothes to impoverished kids and countless similar projects.
The inauguration of the Nelson Mandela Legacy Bridge is scheduled at the icon's birth village, Mvezo, in the rural Eastern Cape province. A science-specialisation high school bearing his name is also due to be opened.
In the United States meanwhile, 17 cities have planned various activities for Thursday.
On Saturday, Australian city Melbourne will hold a concert featuring local and African artists, while a music festival later this year in Norway will promote equality in schools.
Mandela's peace-making spirit has won him worldwide respect.
"Never before in history was one human being so universally acknowledged in his lifetime as the embodiment of magnanimity and reconciliation as Nelson Mandela," archbishop emeritus Desmond Tutu, himself a Nobel peace laureate, said.
Former US secretary of state Hillary Clinton said her family had been inspired by "a man who personifies the best of humanity".
"He is proof that even the most intractable problems are surmountable, that division can be overcome with dignity and forgiveness can triumph over fear," said Clinton.
His health has recently improved, according to official statements and comments from family and friends. His successor as president, Thabo Mbeki, even suggested he might be discharged from hospital in time to spend his birthday at home.
Archbishop emeritus Desmond Tutu has appealed to the Mandela family not to besmirch Mandela's name.
But the messy public dispute showed how difficult it is for even Mandela's own family to live up to his principles of humility and unity.
