Nelson Mandela's Memorial Service In FNB Stadium Johannesburg (SEE PHOTOS)

Is this REALLY the time to take a selfie? David Cameron and Barack Obama took a picture of themselves alongside Denmark's prime minister Helle Thorning-Schmidt during memorial service for Mandela. As the trio posed for the mobile phone snap, Obama's wife Michelle sat alongside her husband looking less than impressed.

Hundreds of world leaders gather in Johannesburg's FNB Stadium for Nelson Mandela's memorial service. Barack Obama paid tribute to anti-apartheid icon, saying 'We will never see the likes of Nelson Mandela again'.

Obama had earlier paid an emotional tribute to Nelson Mandela, calling the South African leader a 'giant of history' as he spoke in a stadium where around a third of the seats were mysteriously left empty. 

He was joined by ex-Presidents George W. Bush, Bill Clinton and Jimmy Carter at the ceremony.

David Cameron, Nick Clegg and Ed Miliband were there along with every living former Prime Minister of the UK.

For the thousands of mourners inside Johannesburg's FNB Stadium it was meant to be a fitting tribute to a 'giant of history'.

But while some reflected on the remarkable life of Nelson Mandela, some world leaders saw it as the perfect opportunity to grab a quick 'selfie' with their peers.

Eulogy: U.S. President Obama waves to the crowd as he delivers his speech at the memorial service for Nelson Mandela in Johannesburg




Passion: Mr Obama spoke of how he was inspired by Mandela's political mission when he began his own career



Fitting setting: A general view of the arena which was the location of Mr Mandela's first speech in Johannesburg after he was released from prison in 1990




Rare display of unity: President Obama shakes hands with Cuban leader Raul Castro in spite of the animosity between their governments



Historic: The handshake between Obama and Fidel Castro's brother Raul came during a ceremony that focused on Mandela's legacy of reconciliation





'His triumph was your triumph': President Barrack Obama is shown on a big screen as he delivers his eulogy to flag-waving and umbrella-holding mourners




Mutual respect: President Obama speaks to Nelson Mandela's widow Graca Machel during the memorial service



Giving his condolences: President Obama kisses Nelson Mandela's widow Graca Machel during the memorial service



Leaders: Tony Abbott, John Key and David Cameron, prime ministers of Australia, New Zealand and Britain respectively, at the service



Support: Gordon Brown, who paid tribute to Mandela in the Commons yesterday, with his wife Sarah and George W. Bush