King Charles III has been diagnosed with "a form of cancer" and has been told to step back from his public duties while he receives treatment, Buckingham Palace says.
The Royal Family announced the news in a statement on Monday.
The news comes partway into Charles' second year on the throne.
Charles, 75, was hospitalized in late January for what the palace says was a "benign prostate enlargement."
However, doctors apparently found a "separate issue of concern" during the procedure and have since identified it as cancer.
Buckingham Palace didn't share the exact details of the cancer, but the king began regular treatments for it on Monday.
"He has been advised by doctors to postpone public-facing duties," the palace said, adding that he will still do official apperwork and state duties.
"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 public duty as soon as possible."
Buckingham Palace added that he "chose" to share his diagnosis in order to cut down on speculation and raise awareness about cancer.
Best wishes have been pouring in since the king's diagnosis first broke on Monday.
"I, like Canadians across the country and people around the world, am thinking of His Majesty King Charles III as he undergoes treatment for cancer," tweeted Prime Minister Justin Trudeau. "We’re sending him our very best wishes – and hoping for a fast and full recovery."
Canada's Governor General Mary Simon also offered her "best wishes" to the king.
"His Majesty has always led with passion and he has always endeavoured to inspire others to create a better world. Today, with this news, he once again is leading by example," she said in her statement. "Seeing His Majesty acknowledge cancer so openly and publicly will hopefully encourage and motivate those who are struggling with their own treatment. We admire The King’s strength and determination as he confronts this disease."
Charles became king in September 2022 after the death of his mother, Queen Elizabeth II, at the age of 96.
Many countries in the Commonwealth, including Canada, are in the process of turning over their currency to reflect the new monarch.
Prince William is next in line to the throne.
