Pope Francis had a previously unannounced meeting at the Vatican on Wednesday afternoon with Britain's King Charles and Queen Camilla, during their state visit to Italy, Buckingham Palace and the Vatican announced.
Charles and Camilla had been due to make a formal state visit to the Vatican, but postponed their plans after doctors prescribed Francis two months of rest after the pontiff experienced a serious bout of double pneumonia.
The pope met the royal couple privately and offered his best wishes for their 20th wedding anniversary, which they celebrated on Wednesday, said a Vatican statement.
Buckingham Palace said Charles and Camilla "were delighted The Pope was well enough to host them - and to have had the opportunity to share their best wishes in person."
Britain's history with the Catholic Church
As British monarch, Charles heads the Church of England, which split from the Catholic Church in 1534.
Francis and Charles have met twice previously in 2017 and 2019, before Charles became king. The late Queen Elizabeth II visited Francis at the Vatican in 2014.