Prince William hosted an investiture ceremony at Windsor Castle on Wednesday. The event marked the Prince of Wales' first royal engagement since King Charles' cancer diagnosis. Experts say William will step up in his father's stead, particularly since Kate Middleton is recovering from surgery. Then, on Monday, Buckingham Palace revealed King Charles had been diagnosed with an unspecified type of cancer and started "a schedule of regular treatments" in a statement shared with BI. Prince William and Kate Middleton.

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Persons: Prince William, Prince, Wales, King Charles, William, Kate Middleton, —, Princess, Buckingham, Kate, Eric Schiffer, King Charles and Queen Elizabeth II, Prince Harry, Charles Organizations: Windsor Castle, Service, Kensington Palace, Business, BI, Associated, Management, CNN Locations: Windsor, Wales, Kensington