King Charles has been forced to take up a daily habit he has famously refused to do for years.
His Majesty, who was diagnosed with cancer in February this year, makes no secret of his preference to skip lunch.
A midday meal, according to the King, is a luxury he cannot afford when coupled with his busy and demanding work schedule.
Much like the late Queen Elizabeth II's corgis, the King's distaste for eating lunch has become one of his most talked about attributes and has even been formally acknowledged by Clarence House in a list of 70 facts released for the King's (formerly Prince Charles) 70th birthday. Without explanation, number 20 on the list is: "The Prince does not eat lunch."
According to a report in the MailOnline, the King has been encouraged by his wife, Queen Camilla, his doctors, and aides, that he must start eating lunch in order to keep his strength up during his ongoing treatment for cancer.
The monarch is said to be "reluctant" about the change, and has compromised by eating half an avocado at lunchtime rather than a full-sized meal.
While there is limited scientific research to suggest specific foods can help slow cancer growth or improve treatment effectiveness, it is important for patients to maintain a healthy, balanced diet during cancer treatments to help keep their strength up.
According to the NHS, cancer treatments disrupt the way cancer cells grow and divide but they can also affect normal cells, which can affect the immune system and make patients feel very unwell.
"Eating well means eating a varied and balanced diet," says the NHS.
"This will give your body all the nutrients it needs to function well during cancer treatment. These nutrients include proteins, carbohydrates, fat, vitamins, and minerals."
King Charles is very particular about his daily diet
Aside from his preference to skip lunch, the King's peculiar penchant for a boiled egg is another of his unusual diet quirks.
Netflix's The Crown even made reference to the monarch's peculiar preference, with Camilla Parker Bowles (played by Emerald Fannell) telling a young Princess Diana (Emma Corrin): "They made the cardinal mistake of refusing to put a soft boiled egg on top."
In a new interview, the King's stepson Tom Parker-Bowles gave a rare insight into the monarch's system for leftovers. "Everything is recycled," he said. "If anything is left over, that will be made into something else or appear the next day. Nothing's thrown out."