Paul Rhys who plays Hubbard was in a drama called Gallowglass in 1993. Gallowglass is Matthew's nephew in the show.
Matthew Goode, Amanda Hale and Tim Hughes all played people connected to royalty in other productions. Matthew Goode played Anthony Armstrong-Jones the husband of Queen Elizabeth's sister Princess Margret on The Crown, Amanda Hale played Lady Margaret Beaufort in The White Princess, and Tom Hughes played Queen Victorias husband Prince Albert in the TV show Victoria.