The casting news had long been rumoured, but the streaming service waited until now to officially confirm the news.
In a statement, Anderson said, “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.”
Fans of the show were quick to share their excitement at the news on Twitter:
The third and fourth seasons of the show will feature a new cast as the royal family with Olivia Colman taking over from Claire Foy as Queen Elizabeth II.
Colman spoke to Entertainment Weekly recently and revealed she has the “worst job”.
“Everyone loves Claire Foy so I have got the worst job in the world at the moment,” she joked.
She spoke about her casting, telling the mag, “I was incredibly uncool about it.”
“The producers went, ‘So…’ [I said,] ‘Yes! Yes! I’m really excited! Thank you very much!’ I loved the first two seasons.”
Tobias Menzies takes over from Matt Smith to star as Prince Philip, Helena Bonham Carter replaces Vanessa Kirby as Princess Margaret and Josh O’Connor will star as Prince Charles.
Bonham Carter revealed to EW that she actually met Princess Margaret once before, “My uncle was actually very close to her… She was pretty scary. At one point, she met me at Windsor Castle and she said, ‘You are getting better, aren’t you?’”
The actress added she believed she was referring to her acting ability, “I presume that’s what she meant.”
In the third season, we’ll also meet Emerald Fennell as Camilla, who we now know as the Duchess of Cornwall, and Princess Diana will be played by Emma Corrin in season four.
EW reports that season three will take place between 1964 and 1976.
The Crown season three will be available on Netflix from November 17.