The Queen has visited the King as he remains in hospital for a third day after undergoing a procedure for an enlarged prostate.

Camilla smiled as she arrived at The London Clinic in central London by car just before midday on Sunday.

She left the hospital just over three hours later, at 3.10pm.

It is the same hospital where the Princess of Wales is being cared for following abdominal surgery.

She visited for a second time between 6pm and 7pm.

The Queen’s visits on Sunday were her third and fourth to the private hospital since she arrived with Charles on Friday morning ahead of the procedure.

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

After he was admitted on Friday, Charles took time to visit his daughter-in-law, Kate, who is in the same hospital.

She is now on the 13th day of her hospital stay after undergoing a successful major operation last week.

A Buckingham Palace spokesman previously said the King 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.

The King 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.

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

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

The exact nature of the 75-year-old’s treatment is not known.

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.

The Queen had previously said her husband is “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.