Former President Nelson Mandela's spirit is still alive, his widow Graça Machel said on Mandela Day on Tuesday.

“His spirit is still alive here with us,” she said to loud cheers from the audience at the launch of the Walk Together initiative by The Elders at the Cape Town International Convention Centre (CTICC). She then invited them to join her in singing Mandela happy birthday. Machel was addressing an estimated 1000 people at the event.

During her address, she told the crowd that South African youth were the shapers of their own world and should partner with others to work toward a future Mandela can be proud of.

“Don’t be shy – take action, be bold, change your world and make it bright, fair, just – exactly the world you aspire to be your world and the world of your children,” Machel said.

“You are the shapers of your own world, you are the builders of your own future.”

The event also marked the ten-year existence of the Elders, a group of global leaders working together for peace and human rights, which was founded by Mandela in 2007.

Mandela would’ve been 99 on Tuesday. He died, aged 95, in December 2013.

Machel said in a world of despair following the 2008 economic meltdown, the Walk Together initiative aims to promote and celebrate "freedom teams" linked to Mandela’s life.

The initiative will promote one organisation each week for the next 52 weeks in the lead up to Mandela’s 100th birthday in 2018, she said.

“In the year ahead we want to build a bright web of hope [and an] abundant global civic space where freedom is celebrated and promoted, and compassion and courageous conversations are encouraged,” Machel said.

The Elders members Pakistani human-rights activist Hina Jilani, former Chilean president Ricardo Lagos, former president of Ireland Mary Robinson, and three term Norwegian Prime Minister Gro Harlem Brundtland were all in attendance.

During her brief opening address, The Elder's deputy chairperson Brundtland said she hoped the Walk Together initiative will reignite a passion to better the world.

Speaking to News24, business mogul Richard Branson who was also in attendance said it was important for business leaders to support initiatives such as Walk Together to "solve the problems of the world".

“Entrepreneurs can sometimes see things in an entrepreneurial way, they can see how maybe to wipe out unnecessary blindness or how to maybe get nurses into the last mile of the rural country side, to maybe campaign on climate change or conflicts,” Branson said.

Asked whether Walk Together could possibly change the current trajectory of South Africa, Branson said change can only occur if South Africans make a decision to change themselves.

“I think The Elders would speak with one voice in the same way in that Archbishop Desmond Tutu has spoken and that is to say that every country needs a leadership that is democratic, honest and rule for the sake of the people and not for the sake of themselves and it is up to the South African people to ask themselves whether that is the kind of leadership they’ve got,” he said.