Malawian President Peter Mutharika joined Commonwealth Heads of State at a state banquet hosted by Queen Elizabeth II at Buckingham Palace in London on Thursday.
The banquet capped off the first official day to the Commonwealth Heads of Government Meeting (CHOGM) in London.
The leaders from all but two of the 53 Commonwealth nations are spending the next two days at CHOGM discussing a range of topics including security, trade and climate change.
In an unusual move, the Queen also appealed to Commonwealth leaders to appoint her son, Prince Charles, to take over from her as head.
She said it was her "sincere wish" that the Prince of Wales one day take over the position.
The role is not hereditary and so will not pass automatically to Prince Charles on the Queen's death.
Mutharika and other leaders are to decide on the successor on Friday when they meet y at Windsor Castle, west of London..
But t leaders were likely to confirm Charles as successor to his mother, who turns 92 on Saturday.
"It is my sincere wish that the Commonwealth will continue to offer stability and continuity to future generations and will decide one day the Prince of Wales should carry on the important work started by my father in 1949," Her Majesty the Queen said.
Britain also hopes to use the biennial two-day summit as a launch pad for stronger trade ties with Commonwealth countries after the U.K. leaves the European Union next year.
Michael Lake, director of the Royal Commonwealth Society charity, said the Commonwealth could be a "useful and productive stepping stone for the development of a new soft-power agenda."
Gay-rights activists are also protesting at the summit, urging the repeal of laws against homosexuality that are in effect in more than 30 Commonwealth countries -- in many cases, introduced under British rule.
Human rights campaigner Peter Tatchell, who attended a small protest outside the summit, said : "Commonwealth leaders need to realise that we are not asking them to accept or approve of homosexuality, we're simply asking them to stop the persecution."
The Commonwealth is officially committed to democracy and human rights, but its rights record is mixed. Many look with pride on the organization's role in the 1970s and '80s in trying to end apartheid in South Africa.
But many Commonwealth nations have been plagued by corruption or destabilized by coups. Zimbabwe's former president, Robert Mugabe, pulled his country out of the group in 2003 after it was suspended for widespread human rights abuses. Gambia quit in 2013, calling the Commonwealth a "neocolonial institution." It rejoined earlier this year.
Still, the Commonwealth provides support for democracy and corruption-fighting, and gives its smaller members a chance to be heard as part of an international network. Attempts to expand the club beyond former British colonies have had modest success, with Mozambique and Rwanda joining in recent years.