Anderson will first appear in Season 4 of the Netflix drama. Word of her casting comes well ahead of Season 3, which does not yet have a premiere date but is expected to launch sometime in 2019.
As previously announced, Season 3 of The Crown will jump forward to the 1970s. Olivia Colman (Broadchurch) will take over the role of Queen Elizabeth II from Claire Foy in Season 3, while Tobias Menzies (Outlander), Ben Daniels (The Exorcist) and Helena Bonham Carter will respectively play the ’70s versions of Prince Philip, Lord Snowdon and Princess Margaret. Rounding out the royal ensemble are Josh O’Connor (Ripper Street) as Prince Charles, Emerald Fennell (Call the Midwife) as Camilla Parker Bowles, Erin Doherty (Call the Midwife) as Princess Anne and Marion Bailey (Allied) as the Queen Mother.
The introduction of Thatcher would indicate that The Crown‘s fourth season will enter the 1980s. Thatcher served as Britain’s first female Prime Minister from 1979 to 1990.
Netflix declined comment for this story.