Manville takes on the role of Queen Elizabeth II's younger sister, previously played by Vanessa Kirby in seasons one and two, as well as Helena Bonham Carter in seasons three and four. "I could not be happier to be playing Princess Margaret," Manville said via the show's Twitter feed. "The baton is being passed on from two formidable actresses, and I really don't want to let the side down. Furthermore to play siblings with my dear friend Imelda Staunton will be nothing short of a complete joy."