Yes, Prince (now King) Charles III (November 14, 1948, at Buckingham Palace, London, England) and Lady Diana Spencer, later Diana, Princess of Wales (born 1 July 1961 at Park House near Sandringham, Norfolk), were related to each other distantly - twice. They were 16th cousins, once removed, by way of descending from Tudor King, Henry VII. It is also said they are 7th cousins, once removed, by being descendants of William Cavendish, who was the 3rd Duke of Devonshire.

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