Claire Foy Queen Elizabeth II Actor Matt Smith Prince Phillip Actor Victoria Hamilton The Queen Mother Actor Jared Harris King George VI Actor Vanessa Kirby Princess Margaret Actor Eileen Atkins Queen Mary Actor Anton Lesser Prime Minister Harold Macmillan Actor Peter Morgan Writer, Executive Producer Stephen Daldry Executive Producer Philip Martin Executive Producer Andy Harries Executive Producer Suzanne Mackie Executive Producer Tanya Seghatchian Executive Producer Robert Fox Executive Producer Matthew Byam-Shaw Executive Producer