What's your number one beauty hack…

‘Don’t over-pluck your eyebrows. When I was little, I had a nervous tick where I’d pull them out at school and my mom warned me they wouldn’t grow back. I modelled briefly in the 90s and also did the Kate Moss super-thin brow thing against everyone’s advice. Luckily, they eventually grew back. I like my brows strong, and fix mine up with Tom Ford’s Brow Sculptor pencil, £35.’

Has your getting-ready regime changed since becoming a mum?

‘Well, I’m much more efficient with my time. It really doesn’t take me very long to get ready. Any me-time is best spent relaxing in the bath or doing an at-home facial, just because mentally it’s very restful. I’m also pretty good about taking vitamins and natural anti-virals because, since having my son, getting sick is like the worst thing ever.’

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You’ve played really amazing characters during your career. Who do you think is most like you?

‘It’s who I’m playing now, Melissa in [US TV show] The Last Man On Earth. She’s so laid-back and no-nonsense, with a very simplified beauty regime. I was able to collaborate on that decision, too. After Mad Men and various different movies, where everything was very stylised, I was so ready to just have no time in hair and make-up.’

Does your hair ever not look fab?

‘There were a couple of [Mad Men] episodes where Betty dyed her hair black and, because I was wearing prosthetics on my face, I couldn’t get away with a wig. Two weeks later, I was back to blonde. Before that, I shot a movie where my hair was red, so I went from blonde to red to blonde to black to blonde in, like, four months. At the end of shooting that season, I just chopped it off – it was completely dead. I’ll try to use hair masks a lot, especially when I’m not working. Kérastase Masquintense for fine hair, £29, is my go-to, because it doesn’t weigh mine down. Kérastase Sérum Thérapiste, £20.90, is so great for ends and flyaways to finish off a hairstyle.’

Who’s your top beauty icon?

‘Maybe Marilyn Monroe. I can also relate to the persona she put on for public appearances. In between movie takes, you see her just being her – she doesn’t have that voice or that walk. She was just like a normal chick. Often when I do red carpet, I want to create a character in my mind to get through it because it can sometimes be anxiety-ridden.’

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Would you say Betty Draper’s become a beauty legend?

‘No joke, I was in a salon once getting my nails done for the show, and a girl sat down next to me and said: ‘Do you watch that TV show, Mad Men? Can you give me the Betty nail?’ I was sitting there, right next to her, and dying laughing. It was so funny.’

What are the products that you couldn’t live without?

‘There are a couple of Chanel red lipsticks that I love, but I wear the Boy, £25, shade the most. I like to switch up my scent with the seasons – I use Chanel Sycomore in the cold months and Comme Des Garçons Odeur 53, from £69, for spring/summer. I’ve been using iS Clinical serums just in the last year and they’ve basically changed my life.’