How is the British approach to beauty different from the American?
‘I think we Brits are very low-maintenance. For good or bad, you rarely walk around New York or LA and see women as grungy as you do in London. In the US they always have their hair and nails done, which isn’t big culturally in England. I am not a sleek person in any way. When I look sleek, I feel like I’m pretending. Whenever I'm not filming though, I paint my nails with a bold Chanel colour, like Mythique, £18, and wear Chanel’s Rouge Coco Stylo in Roman, £26, it's my lip amour. It’s the perfect pink shade, and has the texture of a lipstick, gloss and balm in one.’

Were you into make-up as a teenager?
‘I wore smudgy black eyeliner. And I didn’t do anything with my skin until I started getting acne, at which point I did everything possible to get rid of it. I tried a million products, but none of them worked. I had bad skin up until I was 25. I later learned that it was more about diet and hormonal changes.’

Over the years, what’s been the biggest risk you’ve taken with your look?
‘I have dyed my hair virtually every colour imaginable for different films. It got so bad that my hair literally began to fall out of my head! So for the past five years I’ve used wigs, which is the greatest thing that’s ever happened to my hair.’ Speaking to The Cut, Keira revealed that after this interview '‘I’ve received a big box of things for female baldness, and I had no idea what that was about. I can’t tell you how many boxes of hair loss stuff — and there are many on the market — I have at home. And I was like, Wait, does someone know something that I don’t? Am I like bald? I was so confused! I wear wigs for films. Which is a great thing and has saved my hair, because when you are on a film set and they are doing your hair everyday and dying it a million different colours, it does tend to fall out’.

READ MORE: Why Wigs Are Making It Big

How has your routine changed now that you’re a mother?
‘I have naturally crazy, curly hair, and since I’ve had the baby it’s become 10 times thicker. So now I’ve been finding quite a lot of dreadlocks. Tangle Teezer, £10.60, is the only thing that works for detangling my dreadlocks. It gets rid of the kinks without snagging my hair out. I also use conditioner every two or three days. Bumble and Bumble Creme de Coco, £21, loosens my curls and makes my hair smell like coconut. My skin has also become significantly drier with age, so I moisturise and I try to drink as much water as possible. Aside from that, my teeth are always brushed, and I use lip balm. I love Eve Lom Kiss Mix, £16, for night. It’s quite thick, so my lips don’t dry out while I’m sleeping. My new approach is, “Do what you can remember, and don’t worry about it too much.”’

READ MORE: 12 Steps To Kick Your Lip Balm Addiction

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What’s the best beauty advice you’ve ever received?
‘I was told very early on that if a make-up artist tries to take your eyebrows off, that means he or she is absolute s***.’