Please talk us through your look – what drew you to this particular outfit?

“I decided to go for a full-on gown moment because why not? I’m at a festival that I love, for a film that I love, with a designer I love. I wanted to do something special because it’s close to my heart. It’s a Louis Vuitton bustier dress, all silk, floor-length. It’s a beautiful cream, or off-cream, if that’s even a term! The film The Brutalist spans over 30 years but starts in the 1950s and my character is someone who is quite glamorous. What Nicholas Ghesquiére does is extremely modern, but I wanted to incorporate that 1950s feel to it, and when he sent the drawing of the dress it was exactly what I wanted. I call it my wonderful pavlova dress. It’s very mobile and moves a lot, and the fabric has a slight shine to it, so I think it’ll look amazing in the Venice sunshine.”

What makes Louis Vuitton such a great fit for you and your personal style?

“[Ghesquiére] completely changes all of the codes of fashion and readapts them and reimagines them. It’s really fun. Fashion obviously comes in cycles, but he manages to just keep the modernity to it. It’s exciting to have someone that surprises you. Even if I don’t think it will fit me, or it won’t be my style, his pieces always feel really great and empower me to explore another facet of myself.”

How involved do you tend to be with the styling process?

“I have a wonderful stylist called Rebecca Corbin Murray. As much as I have a strong sense of what I like and what I don’t like, it’s lovely to have a stylist who makes you see things in a different scope. They’re so used to operating in a different realm – whereas I’m so character-focused. But Rebecca encourages me to push the envelope a bit. It’s a reminder that we’re celebrating a really cool moment in a film’s journey.”

Martin getting ready with stylist Rebecca Corbin Murray

What kind of fashion makes you feel your most confident?

“I don’t really like thinking about it too much – it’s so part of my job. When I work, we create a character and we spend hours trying on outfits and figuring out which exact pair of flat black shoes will be the right ones. And you do that for hours. So I think for me, in my day-to-day, I just want to get rid of all of that. I’m almost going to the opposite extreme of what I do in my job, so I look for whatever is comfortable and easy, like jeans, shirts – anything cosy. Most of the time I don’t want the faff when I’m deciding what to wear on my own time! I’ve got an amazing wardrobe of amazing clothes, gowns and heels, but I’m only using 10 per cent of that. And I can’t get rid of anything because I love all the pieces so much! So my challenge is to find ways of incorporating that. But I’m not going to wear the stilettos I wore to the Met Gala to go for coffee with a friend. Although maybe I should…”

How has your style evolved over the years?

“Now I’m in my thirties I’m definitely more confident in what I wear, I don’t worry as much. Now I’m more at ease.”

What has been your most memorable fashion moment in recent years and why?

“I’ve worn so many amazing gowns that just picking one would be extremely unfair! There are two that stick out vividly. One was my first Met Gala where I wore a beautiful Miu Miu gown which was beaded to heaven and back. I still have it and every time I carry the box it’s so heavy, it’s insane. It was fun, gorgeous, elegant; very Miu Miu in that cool, young way that Miuccia does so well. My second was in Venice, when I wore a Louis Vuitton body-fitting embroidered black dress to present an award for a French film called The Lovers. I remember thinking I’d have never felt so confident wearing that dress a few years before.”

Whose style have you always admired and why?

“Various French women – like Jane Birkin, Charlotte Rampling – but also Meg Ryan! I loved her in Sleepless in Seattle and In The Cut, she’s got an effortless coolness to her.”

What is your ideal getting-ready set-up?

“I used to watch BBC News all the time, because we’d be in hotels, and then I’d be quite depressed. My hairstylist pointed out it was probably because I was listening to the news all the time… So I started listening to music instead. I like having the same team of people around me, because it’s quite an intimate process; they see you just before you ‘go on’, so it’s nice to have familiarity where you don’t have to cater to meeting new people. And I’m definitely a people-pleaser so I’d be going out of my way to talk to people and make them feel comfortable.”

Martin with hair stylist Peter Lux

Fashion has a reputation for being frivolous, but why does what we wear matter?

“I think it matters because it’s the first thing we see when we meet someone. It’s the easiest way of communicating who you are as a person without having to go through a monologue of who you are – it’s a time-saver!”

Hair: Peter Lux

Make-up: Kelly Cornwell

Styling: Rebecca Corbin Murray