‘I felt very embarrassed being in the pool with those kids doing amazing dives, while I just stood there in a flowery dress,’ Clémence Poésy reveals as she pops a mint into her mouth. ‘They were probably wondering what the f*** I was doing there!’ We’re in a car post-InStyle shoot, leaving a sports centre in south London’s Crystal Palace for Hackney in east London, where the French actor and Lagerfeld muse calls home. She’s ill with a cold and is bundled up in the back seat in a Christophe Lemaire tweed coat, teamed with an Acne jumper and jeans. ‘Actually, most of my wardrobe is Acne,’ she admits. We’re stuck in rush-hour traffic, and if it hadn’t been for me suggesting we chat en route, I get the feeling Clémence would have jumped on the tube home – which is pretty radical for someone who’s appeared in Harry Potter, In Bruges and 2012’s cult TV drama Birdsong, alongside Eddie Redmayne. Despite all this, Clémence says she only gets recognised occasionally in London, but the return of The Tunnel – an Anglo/French adaption of the Nordic noir The Bridge – might well put an end to her anonymity when she’s topping up her travel card.
You grew up without a TV. Were you an arty family?
‘My parents took me and my sister to watch lots of films, and to the theatre. At some point they caved in and got something that could play tapes and films, and pretended that the TV part didn’t work. We bought it until we caught my dad watching tennis.’
Did you and your sister put on plays?
‘We’d start big stories, but it was just between us – they weren’t for anyone else to see. They’d last for hours, sometimes days, and we’d invent them as movies. We never filmed them, but we even did credits at the beginning.’
When did you realise you could make a career out of it?
‘Well, my dad did theatre, so I always knew it was a thing. Growing up, I wanted to do costumes or drawing. Then, during the school holidays I started doing little parts. I didn’t think of it as a job until it became one.’
Have you experienced Harry Potter fan mania?
‘Once there were some sweet boys waiting outside a theatre wearing Hogwarts costumes. Because my part was so small, I never knew it was going to make such a difference in my life. I remember I had to choose between going to the equivalent of RADA in France and doing Harry Potter. At the time I thought it was going to be a really small thing, but I’m still asked about it in every interview I do as the scale of it is so big.’
And now you’re playing Kate in a film called The Ones Below. She seems like a bit of a loner…
‘I think she is incredibly lonely. Kate watches people more than she does things; she observes life more than she experiences it. So it was an interesting character to approach.’
Do you enjoy red-carpet events?
‘There’s a fun element to it. I’ve been doing it for a while so I have relationships with some designers, which I treasure as they’ve become friends. Well, not friends, that’s a big word. I love Erdem – he’s lovely. And I like what Clare Waight Keller does at Chloé. I don’t have a stylist; it’s fun to do it on your own. If you make mistakes at least they’re yours!’
Tell us some French beauty secrets…
‘There’s a really good product called Collosol. You can use it on everything, even babies’ bottoms. It cleans your skin, but you don’t need to wash it off.’
You’re on Instagram and Twitter, but we’re yet to see a #selfie?
‘Selfies will kill us. I really didn’t want to join, but there was a fake account that people started believing was mine. I only post covers of books, posters for films and sometimes music. I try not to use it as a tool for endless self-promotion. I think it’s going to change our brains, but not for the better. That kind of self-centred thing – how did we go from people inviting us round to show us their holiday albums, and thinking that was the most boring way to spend an evening, to this?’
You play a detective called Elise in The Tunnel. Are you into the crime genre?
‘Not really. I was always more interested in telling the story of the friendship between my character and Karl [played by Stephen Dillane]. I think it’s quite rare that you get to watch a man and woman working together and not falling in love or ending up in bed together.’
The sex scenes in Birdsong got a lot of attention. Are you comfortable with on-screen nudity?
‘It depends on the film and the story you’re trying to tell. You can be comfortable one day and then not the next. Or comfortable with what it brings to one film and not entirely convinced what it could bring to another one.’
The Ones Below is out now. Watch an exclusive clip below.
Plus check out The Tunnel: Sabotage that starts 5 April on Sky Atlantic.