Charles, who is still being treated for cancer, will embark on the nine-day official trip from October 27 until November 4.

He will travel first to the Bahamas, where he is also head of state, without Camilla, and then on to Guyana for a state visit to mark 60 years of bilateral relations between the UK and the South American country.

Charles and Camilla's trip to Antigua and Barbuda will coincide with the Commonwealth Heads of Government Meeting 2026 which is being hosted in the Caribbean nation from November 1 to November 4.

News of the King and Queen's overseas duties was announced shortly after the Duke and Duchess of Sussex returned to the UK to set up home.

Harry and Meghan reportedly landed at Birmingham Airport with their children just before midday on Wednesday, but Charles and Camilla are currently on their annual summer break at Balmoral.

Buckingham Palace said the tour would 'celebrate communities, cultures and nature within the Commonwealth family'.

The King, as the Prince of Wales, visited Antigua and Barbuda in November 2017, following the widespread devastation caused by Hurricanes Irma and Maria.

It will be Camilla's first official visit to Antigua and Barbuda.

Charles previously made official visits to Guyana in 2000 and the Bahamas in 1973.

He is making the state visit to Guyana at the invitation of the president and at the request of the UK Government.

Meanwhile, Prince Harry, Meghan and their children Prince Archie and Princess Lilibet arrived back in Britain this afternoon as they returned after six years in the US.

The Duke and Duchess of Sussex landed at Birmingham Airport around midday after flying on a private plane from California to start their new life in the country.

The couple are thought to have travelled with the children on a Bombardier Global Express XRS luxury long-range business jet, from Van Nuys Airport in Los Angeles.

They chartered the jet with Planet Nine Private Air, a California-based private aircraft operator. Hiring it is believed to cost about $12,000 (£9,000) per hour of flight time. 

The family are understood to have been given no police protection for their arrival, amid ongoing questions over whether taxpayers will foot the bill for their security. 

The Sussexes – who are also believed to be bringing their dogs Mia and Pula across the Atlantic – are now setting up their home in the UK. They plan to live as an “international” family, keeping their homes in California and Portugal.

It marks a shock development after they quit the working monarchy in 2020 and bought a house in Montecito.

Former Suits star Meghan is said to be pursuing an acting role amid reports that she remains in talks about a role in the third series of Guy Ritchie's The Gentlemen.

Harry, 41, and Meghan, 45, will live in a non-royal residence outside of London and the children have both been enrolled in UK schools ready to start next week.

It comes a month after the couple took Archie, seven, and Lilibet, five, to see their grandfather the King for the first time in four years at his Highgrove home in July.

The couple are not thought to have raised the prospect of a return to the UK at that meeting. The King was told they were moving back three days before it was revealed.