Now that "The Crown's" third season has hit Netflix, it's time for fans of the show to start thinking about the fourth season. The third season replaced the entire cast that had been established from the first two seasons, as Queen Elizabeth II continues to age in the world of the show.
As a result, Claire Foy, who had starred in the role, was replaced by Olivia Colman. This wholesale replacement makes "The Crown" totally unique on TV. Most shows keep their casts for the duration of their run.