“I have always wanted to be in a rom-com,” muses Carey Mulligan. Her admission comes as something of a surprise, given the nature of the actor’s previous screen credits – from the suicidal sister of a sex addict in Shame to a radicalized laundry woman in Suffragette. But, apparently, she means it: “I’ve been campaigning for [Love Actually rom-com legend] Richard Curtis to write me something for about 10 years!” she reveals.

The day we meet, Mulligan is dressed soberly in a baggy navy knit, wide-leg black pants and an oversized brown coat. We’re having coffee at a west London members’ club where the actor is a regular, and she looks relaxed and cheery, having “jogged” part of the way here so she wouldn’t be late. She has a place around the corner, but only comes to London for work, spending most of her time at the Devon farmhouse she shares with her musician husband Marcus Mumford [lead singer of Mumford & Sons] and their two children, Evelyn, four, and Wilfred, two.

Mulligan’s rom-com revelation is relevant because the 34-year-old might initially have thought she had landed one with Promising Young Woman, a movie penned and directed by Killing Eve showrunner Emerald Fennell. “It’s funny, because the reaction I first had when I read the script was, ‘This is soooo romantic’,” she says, almost swooning. “There’s this gorgeous ’80s rom-com in there, with this really believable relationship in the middle of it.” Underpinning it, however, is a black comedy about revenge, sexual assault and toxic masculinity.

“Emerald was very deliberate about not putting anything in the film that we haven’t seen in a rom-com or bro-comedy in the past 20 years,” she says. “Emerald’s [point] was: if [you] take someone home and they are really drunk, and then that person reveals they are not drunk, and you feel guilty, then you know what you are doing isn’t right. What we reflected on, making this film, was the amount of real-life stories like this we know. A lot of this film is stuff that pretty much every woman I know has experienced in some way.”

Given the movie’s focus, talk turns to the changes that Mulligan has witnessed in her own industry on the back of #MeToo. “The first concrete measure I saw was doing a play at the Royal Court called Girls & Boys. They gave us a document that was a code of conduct. It was funny because I was the only person in the play,” she recalls. “But the director, the assistant director and writer, we all had to read and sign it. I had never had that in my career. If that had been going on when I started at 18, it would have felt different. Now, I really think it would be wild for something to happen on set. No one would turn a blind eye.”

Their closeness echoes another key theme of the movie – the endurance of friendship. It’s something Mulligan recognizes in her personal life, too. “My female friendships have become increasingly important – particularly the ones with friends I made when I was 14 at school. It’s something about doing stages of life together and supporting each other,” she says. “Every year, we do our birthdays together, because all our birthdays are within six days of one another. It’s great.”

It’s with her closest friends that she can share her fears, too, particularly around “the exposure of the industry, being talked about, Twitter and all that stuff”. Mulligan is notoriously private about her home life. She hates being photographed and doesn’t enjoy red carpets. “When I’m on the red carpet, whatever I’m wearing, I am ultimately myself,” she says. “People say, ‘Pretend you’re Cate Blanchett’. And I do go to red carpets thinking, ‘Be Blanchett. Try and be cool. Smiling with your eyes’, but it doesn’t work.” Does Cate Blanchett smile with her eyes, I ask? “She smiles, but she has this amazing smile that is just her eyes,” Mulligan confirms. When I ask her to show me, she blushes. “I can’t, I can’t. So unfair!”