King Charles has been pictured for the first time since his cancer diagnosis was made public, after the Duke of Sussex arrived in the UK to visit him.
The King and Queen were pictured in a car leaving Clarence House in London, and are now at Sandringham in Norfolk.
Prince Harry arrived in London after an overnight flight from the US.
Buckingham Palace announced on Monday that the King, 75, had been diagnosed with a form of cancer and would step back from public duties for treatment.
The Palace has disclosed few details about the King’s diagnosis, other than to confirm it was discovered during a recent procedure to treat an enlarged prostate.
Both of his sons were informed about his diagnosis before the announcement.
The King and the Queen smiled and waved as they left Clarence House, their home in London, on Tuesday.
Charles and Prince Harry met for around 45 minutes before the King left for his flight to Sandringham.
The Duchess of Sussex is expected to remain in the US, where the couple live with their two young children.
There are no plans for Prince Harry to meet his brother, the Prince of Wales, during his visit to London, the BBC understands.
Prime Minister Rishi Sunak earlier told BBC Radio 5 Live the King’s cancer had been “caught early” and said he was still in “regular contact” with the monarch.
He said their weekly audiences would continue to take place during the King’s treatment.
The speed with which Prince Harry has hurried from California to visit his father in the UK appears significant.
There had already been signs of the family getting closer, such as when the duke, 39, spoke to the King by phone for the monarch’s birthday last autumn.
But there were no signs of Prince Harry or Meghan heading over for Christmas or for any other family get-togethers. Until now they had stayed an ocean apart from the rest of the Royal Family.
Tensions in the Royal Family – as reported in Prince Harry’s memoir Spare – seemed not so much between him and the King, but rather with his brother the Prince of Wales and fuelled by the excesses of the tabloid press.
To that end, Prince Harry’s recent trips to the UK have been more about law courts than the royal courts.
But even before this latest health news, Prince Harry and Meghan – who live in the exclusive Californian community of Montecito – seemed to be planning more projects and travel.
They travelled to Jamaica for a film premiere and had said they would be in Canada later this month, in an event related to their Invictus Games. That trip is still expected to go ahead.
Prince Harry’s brother, Prince William, is yet to comment publicly on the King’s diagnosis.
Prince William is expected to take on some of his father’s public engagements during the King’s absence, though the Palace has stressed the monarch will continue to carry out formal constitutional functions.
The prince was already due to return to his own public duties this week after stepping back following the Princess of Wales’s abdominal surgery last month.
On Tuesday morning, the King’s niece Princess Beatrice was seen arriving at Clarence House.