The Crown: Gillian Anderson explains how she transformed into Margaret Thatcher for season four

Photograph: Des Willie/Netflix

Gillian Anderson has described her transformation into former Prime Minister Margaret Thatcher for The Crown.

The fourth season of Netflix’s royal drama focuses on the exploits of Queen Elizabeth II during Thatcher’s tenure as PM.

Thatcher, whose life was previously dramatised in the Oscar-winning 2011 film The Iron Lady, remained a controversial figure throughout her lifetime.

Speaking to Harper’s Bazaar, Anderson said: “I had to get to a point where it's nothing to do with my opinions of her policies, of her actions.

“It is only about her as a human being and her motivation as a politician and as a mother.”

Thatcher, Thatcher, scene-snatcher: Gillian Anderson in costume as the former PM (Des Willie/Netflix)

The Sex Education star also discussed her working relationship with Peter Morgan, her husband and creator of The Crown.

“For [my and Peter's] own sanity,” she said, “and actually for the benefit of the relationship, we had very clear boundaries: 'I am not going to comment on the script, but you are not allowed to comment on the performance!'”

Season four of The Crown is set to debut on Netflix on 15 November. 

Alongside Anderson, The Crown also stars Olivia Colman as Queen Elizabeth, Emma Corrin as Princess Diana, Helena Bonham Carter as Princess Margaret, and Tobias Menzies as the Duke of Edinburgh.