Catherine, Princess of Wales, spent her third day in hospital on Thursday following surgery, as King Charles III was poised for prostate surgery, creating a royal frontline staffing shortage.
The 42-year-old princess, widely known as Kate, is facing up to two weeks in hospital and several months' recuperation after undergoing "successful abdominal surgery", Kensington Palace said on Wednesday.
Charles, 75, who succeeded his mother Queen Elizabeth II on her death in September 2022, will next week have a "corrective procedure" for a benign enlarged prostate, Buckingham Palace said.
Kate's husband, heir to the throne Prince William, has postponed forthcoming public engagements to be at her side at a private London clinic and to care for their three children, media reports said.
Kensington Palace, which has only said that Kate's unspecified health issue is not related to cancer, is not expecting to issue regular updates on her conditions.
But that has not stopped huge media interest, with photographers and film crews stationed outside The London Clinic.
The health scares leave the already slimmed-down monarchy with three of its most senior figures out of action, and Queen Camilla left as the most visible working royal over the coming weeks.
Charles' second wife, 76, was in Scotland on Thursday for a public event at an art gallery.
She will be in Swindon, central England, on Monday to visit a domestic abuse support service.
"It is unheard of, I think, to have three of the most senior royals temporarily out of action, postponing engagements," Sky News' Royal Correspondent Laura Bundock noted.
Charles -- who is also head of state of 14 other countries outside the United Kingdom, including Australia, Canada and New Zealand -- inherited the throne at an age when most men in developed countries have retired.
His last public appearance, alongside Kate and other senior family figures, was at a Christmas Day service at his Sandringham estate in eastern England.
The unexpected health announcements -- a rare show of transparency from royal officials about personal health matters -- scupper several overseas trips that had been in the planning, according to reports.
William and Kate had been set to travel to Rome in the coming months for their first joint overseas visit in two years, multiple UK media outlets said.
There has also been speculation that Charles and Camilla will visit Australia this year.
Charles's sister Princess Anne, 73, who recently completed a tour of Sri Lanka, is said to be ready to stand in for her brother at scheduled events in the next weeks.
The sudden shortage in frontline working royals follows three years of upheaval. The queen's husband, Prince Philip, died a year before her in 2021.
Charles's younger son Prince Harry -- fifth in line to the throne -- and his wife Meghan quit their roles in 2020 and relocated to California.
The king's younger brother Prince Andrew, now eighth in the line of succession behind William's three children and Harry's two, has also been sidelined.
That followed Andrew's disastrous handling of questions about his friendship with the convicted US sex offender Jeffrey Epstein, and his decision to settle a US civil claim for sexual assault without admitting liability.
