In her début scene in The Crown, Gillian Anderson, playing Margaret Thatcher, arrives at Buckingham Palace for her first meeting with Queen Elizabeth (played by Olivia Colman). The monarch waits, fussing with flowers, while Thatcher, in a blaring royal blue suit, enters the room. "Your Majesty," she croons, sweeping to the floor in an "Is she serious?" curtsy.

It's an audible-gasp moment. Anderson has committed. For the rest of the season, the actress immortalizes all 11 years of Thatcher's "Iron Lady" rule, from her controversial privatization of the British economy, to the Falkland Islands conflict, to the rise of the IRA (Irish Republican Army), to her eventual ouster from office in 1990.

It's testament to Anderson's skill that her performance doesn't dissolve into camp. Rather, it's considered and often poignant. More enjoyable still are Anderson's irreverent dispatches from The Crown's set on Instagram, which include riding in a jeep with Colman (in character) and a snap of "Thatcher" with her legs draped over two thrones.

Having been in the public eye since she was 24, when she signed on to play Dana Scully in The X-Files, Anderson, now 52, has paid her dues. Based in London and effortlessly transitioning between American and British personas, she finds herself in a both deserved and enviable position. And if you'd told her back during The X-Files that she'd play Margaret Thatcher one day? She laughs. "F— off!"

Laura Brown: Hello, Gillian! How are you? You're in London on lockdown No. 3, correct?

Gillian Anderson: Yeah, I am. It hasn't actually hit me yet. I've been finishing cleaning out closets and stuff. The vacuum cleaner is a big deal in my life. I bought a new one the first week of lockdown, and it became pretty much my best friend, my lover, my everything — until we got a puppy.

LB: Other than the vacuum, what's been your saving grace during this confinement period?

GA: My kids [daughter Piper, 26, and sons Oscar, 14, and Felix, 12]. My little ones are obsessed with being outside, and I'm very blessed to have access to outdoor space. It's been a godsend that when they're not in school, they want to be outside and not on screens.

LB: Did you work over lockdown at all?

GA: I did. Sex Education [the series centered on Anderson's sex-therapist character, Jean, and her teenage son] pushed its start from July to September. With Netflix protocol, everyone's tested three times a week.

LB: Speaking of sex, in your Twitter bio, you refer to yourself as a "shag specialist." How much does being a shag specialist inform your acting?

GA: As Margaret Thatcher? [laughs] If we're talking about Sex Education, it influences everything because that is absolutely who Jean is. This season was interesting because she's pregnant. She's so much a shag specialist that she's been shagged and is having a baby. She's bearing proof. [laughs]

LB: People love your irreverence on social media, documenting your performances. My favorite is the pic of you as Thatcher with your legs up on two thrones. When were you able to look at your roles publicly with a bit of a wink?

GA: I came to social media quite late in the game. The whole "penis and yoni of the day" thing [that I do] started because of Sex Education. I was wandering around Jean's house, taking pictures of every item because each one is a phallic symbol in some way. When I started posting them, the response was, "You can't do that. You'll be chucked off Instagram." But apparently, I can. [laughs] For most of my working life I've taken the piss. There's a Polaroid of me as Scully with Q-tips up my nose and coming out of my ears. I made wrap T-shirts for the whole [X-Files] crew with that image as a goodbye.

LB: How has taking the piss been good for you?

GA: The business I'm in sometimes takes itself very seriously, and it's easy to take oneself seriously in this business. I've found that the way to survive is to not do that. Part of that is finding ways to allow rejection to roll off your back. You have to keep showing up and moving forward — even after not-great reviews or a flop — and maintain a sense of humor. Of course, there are certain things I don't take lightly at all. I have less of a sense of a humor around emotional stuff and relationships.

LB: The Crown could have been very self-serious, so for you to mess around with the mythology was so great. Tell me about preparing to play Thatcher.

GA: I was really f—ing nervous. At the same time, it's a wonderful production run by adults who have done it before. They shoot the first two weeks of stuff for any big new character on the soundstages. It was comforting to know that if I sucked, it would be easy to reshoot as opposed to renting a countryside mansion for another day because I was bad. I had an intense scene on my first day of work, and I knew that even if I did my absolute best, I'd probably be a bit more in her shoes, her voice, her everything, a few weeks down the road. It made it easier to have that safety net in case I wasn't quite there at the beginning.

LB: Insurance.

GA: Right. And I was working with Olivia Colman and Josh [O'Connor], who had done a whole season before, so they were incredibly relaxed and welcoming. As long as you're prepared, it's easy to breathe between takes and have a joke or a laugh.

LB: From your first scene as Thatcher, your commitment is clear. Especially the voice. How did you feel about it?

GA: I was in a relationship with the show-runner [Peter Morgan] at the time, and I saw so much stuff even before the final cut. Sometimes it would be easy to hear it in another room, and sometimes it wouldn't be. [laughs] I worked very hard on the voice, specifically. It needed to be a particular pitch and way of talking that felt like it would be natural and grounded somewhere in me, and also one that I could keep consistent.

LB: How did you perfect that ironic curtsy?

GA: In order to do that, one needs good balance and a certain degree of musculature in one's thighs. I don't feel like I have particularly strong thighs. I'm not sure I even knew I could do that prior to the scene. [laughs]

LB: But that's why Thatcher's called the Iron Lady, didn't you know? [laughs]

GA: Oh, yes, her iron thighs. Very, very good.

LB: By the way, your physical transformation for the role was impressive — the wigs, the makeup. I looked at one of your Instagrams and was like, "Does she have makeup on?" It's so subtle. That particular eye shadow on Thatcher wasn't too opaque.

GA: I don't know how many colors they must have gone through. What had looked perfect in the makeup room mirror was just wrong when it got in front of the camera. They had to start from scratch again with the base and the color of the eyebrows and the density of the hair and the lips.

LB: Back when you were doing The X-Files, if somebody had said to you, "In 20-ish years, you're going to play Margaret Thatcher," what would you have thought?

GA: F— off! [laughs] I think I would have been quite shocked. I started X-Files so young, at 24. Right after I moved back to the U.K., I was offered [the BBC series] Bleak House. It was exactly the kind of thing I had always wanted to do and thought I should be doing when I got caught up doing The X-Files. I hadn't auditioned, and I'm not sure they knew whether or not I could even do a British accent. But they still offered me the part. That was a big moment for me.

LB: The two biggest shows you've done, The X-Files and The Crown, are wildly different — but they're both wildly watched. What has been the response to your performance on The Crown?

GA: Oddly, the most remarkable thing has been that [the British-Irish psychological thriller series] The Fall, which was originally on BBC [from 2013 to 2016 and starred Anderson as a detective], was relaunched and became No. 1 on Netflix over here during lockdown. Between that, Sex Ed, and The Crown, I had three very different things on Netflix at the same time. So the reaction was very much about that, personally. Most feedback I heard specifically about The Crown came through Pete because he has fancy filmmaker friends. For me, it was college friends coming out of the woodwork and DMing me suddenly. [laughs]

LB: Your interest in the British monarchy is slight, right?

GA: Incredibly slight, yes.

LB: There was the argument about putting a disclaimer at the beginning of The Crown saying it was fictionalized. How did you feel about that?

GA: It's so obvious that we're doing a TV show and that these are characters based on real-life people. To me, it just felt like drama for the sake of drama. But I get that there are a lot of people invested.

LB: And the royals always come off as human beings, which is a testament to the taste and empathy of everybody involved.

GA: Yes, there's a lot of stuff that could have been written about — but was not — that is so much worse than what ended up in the show. There has been kindness extended in certain areas where it didn't have to be.

LB: Back to you. When do you feel like you first really owned your s—, professionally?

GA: I think it was probably around the third season of X-Files [in 1995]. Suddenly there was an episode specifically written about Scully, and it was a good emotional arc. The director, David Nutter, said to me, "This is an opportunity. Show them what you've got." I worked on every minuscule detail, and I think that was the first time I felt empowered by the level of preparation. There was power in that, in the same way that there's power in knowledge. Coming properly prepared gives you a freedom and sense of strength that's pretty cool.

LB: The X-Files, of course, also made you super-famous relatively young.

GA: Even pre-social media, there were paparazzi staked out around the sandpit every time I took my daughter to the park in L.A. People would also rear-end me [while driving] to film my reaction. Thankfully, we didn't have that when we were shooting in Vancouver. We weren't out and about because we literally had no time to do anything, but we could be on location and I didn't have to worry about people outside my front door, following me. Having people hold umbrellas to protect you or worrying about people going through your trash as a 20-something would have been traumatic. I was saved from all of that nonsense.

LB: How ambitious were you then, and how ambitious are you now?

GA: I've never been really ambitious. I feel like I've been the one who has lit the fire under other people from time to time. But then I'll hear about a project or get a surge of desire to do something and then get distracted by real life. I'm a mom first. That said, I do feel a bit ambitious at the minute after The Crown. I'm grateful, and I'm going after things in a way that I might not normally. But I'm not a fighter. If it's not meant for me, it's not meant for me.

LB: Is this the topper of your career to date?

GA: Probably. I do think it's been a progression. When I did [the London production of] A Streetcar Named Desire [in 2014] and played Stella Gibson [in The Fall] that same year, I felt like, "OK, I can die now and I'd be happy." But it's gone on from there. I definitely feel like there's an upswing in the stuff I'm being sent now. It feels good.

LB: You're the gal at the dance.

GA: I'm at the dance, Laura. I'm at the dance.

LB: What are you wearing at the dance?

GA: I'm not wearing pink. [laughs]

LB: Seriously, though, you look fantastic. How do you feel in your skin now?

GA: Thank you. I don't know. I'm out of shape. I'm pretty creaky and flabby. I'm horrible at taking care of my skin.

LB: How do you take care of yourself mentally?

GA: I have a very good support system here in the U.K., and recently I'm finding that to be everything. I really rely on my girlfriends. I have increased my meditation, which always helps. The next thing to do is to not just talk about doing yoga but actually do yoga. [laughs]

LB: In terms of style, when do you feel your best?

GA: I like a good coat. And I like a heel. I'm 5 foot 3, so I need a 9-inch heel. [laughs] Also, it's taken me a long time, but I've found that solid colors work best for me.

LB: A few years ago you also co-wrote a book [We: A Manifesto for Women Everywhere]. How did you think you could be a helpful voice for women?

GA: Initially, my thought was quite naive as in a "Can't we all get along?" type of way. We're all struggling with exactly the same things, so why are we not supporting each other and coming together? My friend [and co-author] Jennifer Nadel had been thinking about similar things. It's a concise compilation of how we stay sane and well physically, mentally, emotionally, spiritually, and how we then translate that into being of service and taking action.

LB: You're in the business of mythology. Do you feel a great desire to remind people that you too are a human lady?

GA: Yeah. I think half of what we're talking about in the book is where we've failed. It's that kind of conversation.

LB: Where is the failing for you?

GA: I fail at yoga! [laughs] I'm absolutely a complainer. I complain all the time, and that's something I'm either actively working at not doing or actively working at doing and refusing to stop. I am completely intolerant of all other human beings, and I constantly have to remind myself to be compassionate and generous and to reach out to people who are struggling. I don't like cars driving by. I don't like other human beings walking behind me. I'm intolerant.

LB: When you get stressed, what's the first thing you eat?

GA: My appetite goes when I'm stressed. When I'm not stressed, I like muesli. If I could eat something for every meal, it would probably be cereal in one form or another. I have muesli for breakfast, and for lunch I have a Coca-Cola — a full-fat Coke — and a protein bar. It's terrible, which is partly why I'm doing a juice fast.

LB: What do you long to do when we all have our lives back?

GA: Travel. I would love to visit friends and family that I love. My sister is pregnant, so I'm going to have to get on a plane in April. But traveling to see friends would be really nice—especially friends who live somewhere warm.

LB: Are you good in your own company?

GA: Yes. I prefer to be alone.

LB: But you've never been "hotter"!

GA: And that's all that matters. Who cares if I'm a bitch and I hate everybody? [laughs]

Lead Image: Prada cape, top, and pants. Bulgari necklace. Manolo Blahnik pumps.

Photography by Charlotte Hadden/Together Associates. Styling by Sam Ranger. Hair by James Rowe/Bryant Artists. Makeup by Florrie White/Bryant Artists. Manicure by Jessica
Thompson/Eighteen Management. Set design by Derek Hardie Martin/The Wall Group; Production by Truro Productions.

For more stories like this, pick up the March 2021 issue of InStyle, available on newsstands, on Amazon, and for digital download Feb. 12th.