His diagnosis came as a shock to the 75-year-old monarch, as well as to his close family and the people of Britain.

After returning to London for further treatment, King Charles made the 150-mile trip back to the royal estate of Sandringham, where he was spotted without his Queen, who had royal duties to attend to.

The King, dressed in a smart suit and tie, waved to well-wishers who had gathered outside Buckingham Palace and along the Mall on February 14 as he began his journey back to Sandringham.

“When the King visits Sandringham, it’s a place where he can get some solace. One of the tour guides mentioned how he enjoys having his breakfast tea and afternoon tea in front of the backdrop of his beautiful gardens. Even when the house is open and he is staying there, the King tends to reside upstairs,” a royal source shared with Hello Magazine.

His return to London was a second one that he took for the cause of receiving treatment, and he’s expected to undergo another treatment later this month, as per Daily Express.

The King’s exact form of cancer remains unknown. It is also unknown at what stage he is.

Buckingham Palace’s initial statement read: “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.”

A source told the Daily Mail that King Charles is “on good form,” but besides that, it is expected that he takes a longer absence from his royal duties.

His younger son, Prince Harry, who returned to Britain for a visit with his father shortly after his diagnosis was revealed, was reported to have offered to step in and play a role while his father receives cancer treatment. However, Buckingham Palace aides reportedly said there was “zero per cent chance” that Prince Harry could be allowed to be working for the royal family during his father’s illness.

Robert Hardman, author of Charles III: New King. New Court. The Inside Story, spoke to BBC Radio 4’s Today program about the King’s duties and said, “I would imagine we probably won’t see him at Westminster Abbey now.