Smiling at waiting reporters, Camilla said the King was “doing well” following the procedure. “He’s doing well, thank you,” she said.
Earlier on Friday, Charles took time to visit Kate, who is on the 11th day of her hospital stay after undergoing the operation last week.
A spokesperson for Buckingham Palace said on Friday: “The King was this morning admitted to a London hospital for scheduled treatment.
“His Majesty would like to thank all those who have sent their good wishes over the past week and is delighted to learn that his diagnosis is having a positive impact on public health awareness.”
The King had returned to London from Sandringham on Thursday ahead of the operation, and on Friday morning was pictured in the back of a car with the Queen on the way to the clinic.
Prime minister Rishi Sunak wished Charles the “very best” for his treatment and a “speedy recovery” afterwards, a Downing Street spokesperson said.
Charles received the diagnosis on 17 January after going for a check-up because he was experiencing symptoms associated with the benign condition.
He approved the announcement so a series of public engagements could be postponed. It’s also understood that he wanted to raise awareness of the condition and encourage other men to get themselves checked.
Benign prostate enlargement, common in men aged over 50, is not a cancer and usually does not pose a serious threat to health.
Since the King shared his diagnosis, the NHS website page on the condition received more than 26,000 visits in the following 48 hours, compared with a daily average of 1,400 visits.
On the same day as Buckingham Palace revealed his diagnosis, it was revealed that Kate was at The London Clinic recovering from her own operation. She was said to be “doing well” – but is unlikely to return to official duties until after Easter.
In another health episode for the Royal Family, last weekend, Sarah, Duchess of York, shared she had been diagnosed with melanoma skin cancer.
The 64-year-old received the news after several moles were removed when she was treated for breast cancer in June, with one found to be cancerous.
She was said to be in “good spirits” as doctors work to establish if the cancer has spread.