Presidents – past and present – global leaders, royals and A-list celebrities have started to arrive at FNB Stadium to pay their last respects at an unprecedented gathering that will hail one of humanity's great peacemakers.

At least 91 Heads of State and Government will put aside world politics for four hours and unite as they recall, reflect, honour and bid farewell to the icon that is Nelson Mandela – a clear sign of the kind of impact that the former South African President left on the world.

President Jacob Zuma has arrived with his wife Thobeka Zuma. Nobel Prize Laureate Archbishop Desmond Tutu arrived moments before.

US President Barack Obama, who will address mourners, has also arrived at the stadium with his wife Michelle Obama. They are accompanied by three former Presidents of the US, including George W. Bush and his wife, Laura, Jimmy Carter and Bill Clinton with his wife former Secretary of State Hillary Clinton and their daughter Chelsea, as well as Attorney General Eric Holder.

Cuban leader Raul Castro – the erstwhile President Fidel Castro’s brother, a long-time friend of Mandela's – is already present. He will deliver a speech later.

Prince Charles, Sir John Major, former UK Prime Ministers Tony Blair and Gordon Brown are accompanying UK Prime Minister David Cameron.

Brazilian President Dilma Rousseff, French President Francois Hollande, Chinese Vice President Li Yuanchao, Palestinian Authority President Mahmoud Abbas are also present.

From the continent, Zimbabwe's Robert Mugabe and Namibian President Hifkepunye Pohamba, who is also scheduled to speak at the service, have arrived.

UN Secretary General Ban Ki-moon, African Union Commission Chairperson Nkosazana Dlamini Zuma, and former UN chief Kofi Annan are also present.

Mandela’s long-time friends George Bizos and Andrew Mlangeni have arrived. Mlangeni will speak at the ceremony.

Among the celebrity mourners are talk show queen Oprah Winfrey and model Naomi Campbell, singer/activist Bono, British billionaire Sir Richard Branson, musician Peter Gabriel and the pop music group Spice Girls.

Mandela's wife, Graca Machel, former wife Winnie Madikizela-Mandela, his family, including his grandchildren – who will pay tribute to Mandela at the ceremony – have also arrived.

The 95 000-seat stadium in Soweto, the township that was at the heart of the anti-apartheid struggle, is the site of Mandela's last public appearance, when he waved to fans from the back of a golf cart at the final of the 2010 Soccer World Cup.

The service is seen as the final chance for grieving South Africans to unite in mass celebration of Mandela’s life before the exclusive State Funeral.

From tomorrow, Mandela’s body will lie in state at the Union Buildings until Friday. He will be buried on Sunday in Qunu, his rural hometown in the Eastern Cape.