The King has held his first audience with Prime Minister Liz Truss at Buckingham Palace.
He became King when the Queen died yesterday afternoon.
Ms Truss only became prime minister on Tuesday, a day after winning the Conservative Party leadership contest.
She travelled to Balmoral that morning to meet the Queen, who then asked her to form a government.
The picture of the two meeting showed the Queen’s last public appearance.
Just 48 hours later, Ms Truss gave a speech on the steps of Downing Street to mark the Queen’s death and offered her support to the King.
Her new cabinet met this morning to pay tribute to the Queen, and MPs and peers remembered her in a special session of parliament.
She was also pictured signing a book of condolence in 10 Downing Street.
The King’s first meeting with Ms Truss comes ahead of his televised address to the nation at 6pm today.
Earlier, King Charles greeted well-wishers outside Buckingham Palace.
It was his first walkabout and encounter with the public since his accession.
One woman leaned over to kiss his right hand and another kissed him on the cheek as he thanked people for their good wishes and shook hands with them.
The King will be proclaimed at the Accession Council at 10am tomorrow morning in the State Apartments of St James’s Palace, Buckingham Palace has said. It will be the first time in history the process has been televised.