Lady Katherine "Kat" Ashley (née Champerowne) was a handmaiden of Queen Catherine Parr and governess of Elizabeth Tudor. She appears as a recurring character in Season Four, played by actress Maude Hirst. With Catherine's private approval, she seeks to educate Elizabeth in favor of Protestantism as a tribute to Elizabeth's late mother Anne Boleyn, who Lady Ashley clearly admired as a martyr of the Lutheran cause.

Kat would later become one of Elizabeth's closest friends, and they remained such during Elizabeth's reign as Queen until Kat's death, which caused Elizabeth to go into a period of mourning.