King Charles is being treated for cancer, Buckingham Palace has confirmed.

The palace confirmed the disease, which is not prostate cancer, was discovered while the King was being treated in hospital for an enlarged prostate.

The 75-year-old has started a schedule of regular treatments but has been advised to postpone his public-facing duties.

The King was seen attending the Sunday service at St Magdalene Church in Sandringham with Queen Camilla on Sunday.

He smiled and waved to the public as they walked to the church accompanied by Rev Canon Dr Paul Williams, rector of the Sandringham group of churches.

He will carry on working behind the scenes on state business and official papers and returned from Sandringham to London on Monday to commence treatment as an out-patient.

Dereham Times: King Charles and Queen Camilla attended church in Sandringham on SundayKing Charles and Queen Camilla attended church in Sandringham on Sunday (Image: Joe Giddens/PA)

In a statement, Buckingham Palace said: "During the King’s recent hospital procedure for benign prostate enlargement, a separate issue of concern was noted. Subsequent diagnostic tests have identified a form of cancer.

"His Majesty has today commenced a schedule of regular treatments, during which time he has been advised by doctors to postpone public-facing duties. Throughout this period, His Majesty will continue to undertake State business and official paperwork as usual.

"The King is grateful to his medical team for their swift intervention, which was made possible thanks to his recent hospital procedure. He remains wholly positive about his treatment and looks forward to returning to full public duty as soon as possible.

"His Majesty has chosen to share his diagnosis to prevent speculation and in the hope it may assist public understanding for all those around the world who are affected by cancer."

The Palace has called for the King’s privacy to be respected, especially during his treatment, but said the monarch wanted to make his diagnosis public because of his long-running support for cancer charities.

A spokesman said: "The King has elected to make his diagnosis public once the schedule of treatment had begun, noting that as Prince of Wales he was patron of a number of cancer-related charities."

Dereham Times: King Charles and Queen Camilla left Sandringham on MondayKing Charles and Queen Camilla left Sandringham on Monday (Image: PA)

King Charles' grandfather, George VI, died aged 56 at Sandringham in February 1952 of a fatal blood clot to the heart and was also revealed to have been suffering from lung cancer.

The King spends increasing amounts of time at the Norfolk estate, where he is heavily involved in farming and the programme of "ecological delivery" which includes hedge and tree planting, along with bird boxes and wide field margins to encourage insects.

Prime minister Rishi Sunak reacted to the news of the King’s cancer diagnosis by tweeting: "Wishing His Majesty a full and speedy recovery.

"I have no doubt he’ll be back to full strength in no time and I know the whole country will be wishing him well."

Prince Harry is reported to be flying back to the UK to see his father this week.

"The Duke of Sussex did speak with his father about his diagnosis. He will be traveling to the UK to see His Majesty in the coming days," said a source close to Harry.

Queen Camilla recently said her husband was "doing his best" following his release from hospital as she opened a cancer support centre at the Royal Free Hospital in London.

The news is the latest health scare to hit the royal family at the start of 2024, coming after the King’s hospital stay, the Princess of Wales’s major abdominal surgery and Sarah, Duchess of York’s diagnosis of skin cancer.