Gillian Anderson went to extreme lengths to play Margaret Thatcher on the upcoming season of “The Crown”.

The actress, 52, who joins season four of Netflix’s beloved royal drama, chatted with OK! Magazine about playing the former U.K. Prime Minister and revealed she wore a fat suit while on set.

“I wear a fat suit,” she explained. “And she has a very particular way of walking.”

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But for Anderson, the suit helped pull Thatcher’s entire look together, “After you’ve been working on a character for a long time, it’s really quite something to see everything come together at the same time.”

“It’s daunting, too,” she added. “The first time you step in front of the camera, you’re exposed and it’s being documented – and you hope you’re on the right track. It’s exciting to finally get there and it’s also a bit freaky.”

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Overall, Anderson is proud of the work she put into the role, “It wasn’t too hard to maintain because she has a lot of breath in her voice. It was fun to do, but it was also a bit challenging to figure out how to not go too overboard and take it into parody. Ultimately, her voice is as quintessential as her wig.”

Anderson previously opened up to ET Canada’s Sangita Patel about joining “The Crown”. Watch the video below for more.

“The Crown” premieres on Netflix on Nov. 15.