King Charles III has been diagnosed with cancer, Buckingham Palace officials announced Monday.
Tests detected "a form of cancer" when the British monarch, 75, underwent a recent hospital procedure for benign prostate enlargement, palace officials said.
A "separate issue of concern" was found by doctors and subsequent tests identified a form of cancer.
Palace officials didn't specify what kind of cancer Charles has, but a spokesperson said it is not prostate cancer.
Charles began a schedule of regular treatments on Feb. 5 and has postponed his public duties for the time being, according to the announcement.
"The King is grateful to his medical team for their swift intervention, which was made possible thanks to his recent hospital procedure," palace officials said in a statement. "He remains wholly positive about his treatment and looks forward to returning to full public duty as soon as possible."
Charles returned to London from his royal estate in Sandringham on Monday morning to begin outpatient treatment, the palace said. He remained at home in London on Monday night.
British Prime Minister Rishi Sunak sent well wishes to Charles following the announcement.
"Wishing His Majesty a full and speedy recovery," Sunak wrote on X. "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."
According to palace officials, Charles decided to disclose 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."
A senior Buckingham Palace source told NBC News that Queen Camilla had visited him at the hospital and that he was “doing well” at the time.
Camilla wasn't expected to miss any coming public engagements following her husband's diagnosis, the palace said.
Charles is not the only royal family member dealing with health issues of late.
The former Kate Middleton is continuing her recovery at home and is unlikely to return to public duties until after Easter, Kensington Palace officials said.