The Prince of Wales will host his first Commonwealth Heads of Government Meeting (Chogm) today.
It will be one of his most significant duties to date as a future monarch as he will be deputising for the Queen on the world stage.
But the gathering of national leaders in Sri Lanka is being overshadowed by concerns about alleged human rights abuses committed by the country's regime towards the end of a bitter civil war in 2009.
The prime minister of India Manmohan Singh and his counterparts Canada's Stephen Harper and Mauritius leader Navin Ramgoolamare are boycotting the meeting in protest.
Among the leaders taking part in the discussions will be David Cameron who will be joined by Foreign Secretary William Hague.
Hosting the Commonwealth summit in Sri Lanka will be a new challenge for Charles who is assuming the role, traditionally performed by the Queen.
The Queen, who decided not to fly to Sri Lanka following a review by Buckingham Palace of her long haul flights, traditionally plays no part in the private discussions that happen between the leaders.
But she is a unifying figure during the three-day summit who will have met all but the very newest presidents and prime ministers.
Charles will have to take on this symbolic role making the leaders feel welcome.
Steve Crawshaw, director of the office of Amnesty International's secretary general Salil Shetty who is in Colombo representing the organisation around Chogm, said: "Prince Charles is clearly in a difficult position representing the Queen who famously avoids politics in all contexts.
"But I very much hope that in private Prince Charles will make absolutely clear how dismayed anybody who cares about human rights would be, seeing what is happening in Sri Lanka today.
"As the representative of the Queen he will no doubt choose his words carefully when speaking publicly, but I hope that even there we will see a reflection and understanding of how serious the problems are that Sri Lanka is facing, and one would hope that will not be swept under the carpet."
In the evening Charles and Camilla will host a banquet for the world leaders.