Charles took part in 372 public engagements last year, even after stepping aside for almost three months because of cancer treatment, according to data compiled by The Times of London newspaper. That made him the second-busiest royal behind his sister, Princes Anne, who had 474 engagements.

King Charles, 76, was photographed leaving his London home on March 28, making the first time he's been seen since his brief hospitalization for side effects of cancer treatment the previous day.

As reported by The Mirror, the King and Princess Kate also aren’t the only royals to have been treated at the hospital before. Prince Phillip and Princess Margaret are also believed to have been patients.