The King is spending the night in hospital after undergoing a procedure for an enlarged prostate, Buckingham Palace has said.

Charles was spotted entering The London Clinic on Friday morning with the Queen at his side – the same hospital where the Princess of Wales is being cared for following abdominal surgery.

Camilla appeared in good spirits when she first left the premises at 3.10pm – smiling at reporters before getting into a car – after which she returned for a visit lasting around an hour and a half before leaving the private hospital again just before 8pm.

She told people inside The London Clinic earlier on Friday that the King was “doing well” after the procedure.

Charles took time to visit his daughter-in-law Kate, who is on the 12th day of her hospital stay after undergoing a successful major operation last week.

A Buckingham Palace spokesman previously said he was “admitted to a London hospital for scheduled treatment”.

The spokesman added: “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.”

It is not known how long Charles will spend in hospital but reports suggest he could remain there over the weekend.

The King arrived back in London from Norfolk on Thursday afternoon, ready for the procedure after squeezing in a couple of behind-the-scenes official duties.

Prime Minister Rishi Sunak wished Charles the “very best” for his treatment and a “speedy recovery” afterwards, a Downing Street spokeswoman said.

He was diagnosed with the benign condition on January 17 while staying at Birkhall, Aberdeenshire, after going for a check-up because he was experiencing symptoms.

The King is understood to have wanted to share the news to encourage other men to get themselves checked.

Charles, who only acceded to the throne 16 months ago, cancelled engagements and was urged to rest by his doctors ahead of the corrective procedure.

The Queen had previously said her husband was “fine” and looking forward to getting back to work

News of his diagnosis came on the same day that Kensington Palace announced the princess was in hospital after undergoing abdominal surgery.

Kate, 42, is not expected to carry out official engagements until after Easter, with the Prince of Wales clearing his diary of official duties for the time being

NHS England said the “enlarged prostate” page on the NHS website received one visit every five seconds on the day the King’s diagnosis was announced, with further huge boosts in visits in the days that followed.