It will feature the same cast as Season 3
After biding farewell to Claire Foy, Vanessa Kirby and Matt Smith at the end of season 2, we're nowhere near ready for another upheavel. Thankfully, production plans to re-cast the series every two seasons, so we still have Olivia Colman, Tobias Menzies, Helena Bonham Carter, and Ben Daniels as the four main characters - Queen Elizabeth II, Prince Philip, Princess Margaret, and Anthony Armstrong-Jones - for season 4.
Princess Diana's storyline will be included
Princess Diana will be played by British actress Emma Corrin. “Beyond excited and honoured to be joining The Crown for its fourth season," Corrin said in a statement released by Netflix. "I have been glued to the show since the first episode and to think I’m now joining this incredibly talented acting family is just surreal. Princess Diana was an icon, and her effect on the world remains profound and inspiring. To be given the chance to explore her through Peter Morgan’s writing is the most exceptional opportunity, and I will strive to do her justice!”
Gillian Anderson will play Margaret Thatcher
Anderson confirmed her role in season 4 via the official The Crown Twitter account, writing in a statement, "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 loved or despised, defined an era."
Prince Charles will play a major role in season 4
Josh O'Connor, who joined as the role of Prince Charles in season 3, hinted at the Prince of Wale being a key storyline going forwards in a statement. "Seasons 3 and 4 will follow some of the most turbulent events in the Prince of Wales's life and our national story and I'm excited to be bringing to life the man in the midst of it all," he said when he was announced as joining the series.
There will be at least two more seasons
"The idea is to do this over six decades, in six seasons presumably, and make the whole show over eight to 10 years," Netflix's chief content officer Ted Sarandos revealed in 2016, per The Hollywood Reporter. This means we'll get another complete recasting before the end of the show and that it'll likely touch on Kate Middleton and Meghan Markle's entry to the royal family.
Season 4 will likely premiere in 2020
Season 1 aired in 2016, Season 2 in 2017 and season 3 in mid-2019 after a delay. This means the fourth season will likely hit Netflix toward the end of 2020 in November or December.