The season three cast, including Olivia Colman, Helena Bonham Carter, Tobias Menzies, Josh O'Connor and Erin Doherty, will all return for the fourth season.
Seasons three and four were shot back-to-back and season three premiered November 17, 2019 with season four still in production at the end of 2019. The series traditionally drops at the end of the year, so the next installment could be the end of 2020.
Claire Foy, the Emmy-winning star of seasons one and two, was spotted filming season four. It appears to be a recreation of Queen Elizabeth's 1947 radio broadcast from South Africa on her 21st birthday.
Season four will introduce Princess Diana and feature her 1981 wedding to Prince Charles.
"I have been glued to the show and to think I'm now joining this incredibly talented acting family is surreal," Corrin said. "Princess Diana was an icon and her effect on the world remains profound and inspiring. To explore her through Peter Morgan's writing is the most exceptional opportunity and I will strive to do her justice!"
Expect to see a different side of this royal. "I don't want to give anything away, but I'll say that hopefully, people will feel sorry for Charles in season three, and then, maybe, we'll change that in season four," Josh O'Connor told Town and Country. "Certainly, it feels like there's a definite shift being told in season three. And all across four, there's definitely a different side to Charles that we're going to see."
Born in 1982, Prince William will make his first appearance in the series in season four. Emma Corrin and Josh O'Connor play his parents, Princess Diana and Prince Charles.
Gillian Anderson will make her The Crown debut as Margaret Thatcher, the prime minister from 1979-1990.
"I am so excited to be joining the cast and crew of The Crown and to have the opportunity to portray such a complicated and controversial woman. Thatcher was undoubtedly formidable but I am relishing exploring beneath the surface and, dare I say, falling in love with the icon who, whether love or despise, defined an era," Anderson said.
Season three was set between 1964 and 1977, and with Gillian Anderson playing Margaret Thatcher, the introduction of Princess Diana and birth of Prince William, we know the show goes into the 1980s in season four. Thatcher was prime minister until 1990.