She was coiffed to within an inch of her life as Lady Penelope in Thunderbirds, but the 27-year-old actress arrives for our shoot working the no-make-up look in a way only the truly pretty can. That said, as David ‘Dr Who’ Tennant’s other half, she’s had to learn a thing or two about getting red-carpet fabulous

Are you a low-maintenance girl?
God, yes. I’d wear a tracksuit on the red carpet given half the chance, although I have started to enjoy getting glammed up now and again. I just have to be careful. For some reason, wearing lips and eyes together makes me look like a drag queen. But it’s probably a lack of confidence that holds me back with make-up.

You had the nerve to get in the buff on-screen though …
I just sped for the best! I’ve got a curvy figure and I try to fly the flag for a healthy body image. When I played an artist’s muse in Art School Confidential, I purposely put on about a stone by eating lots of spaghetti bolognese. I thought, if I’m going to do this, I’m going to make sure I look like a woman.

Which body part are you proud of?
I’ve got quite good tits! I feel quite embarrassed saying that, but I think I lucked out in the breast department. I’m not one to flaunt them though.

You’ve certainly strapped them down for period-drama roles …
I’ve worn far too many corsets and I’ve got quite a lot of back problems as a result. Having weekly shiatsu massages with a lady called Doris Block in Queen’s Park, London, has really helped.

Do you go for other treatments?
I don’t see the point in going to a salon when I can use all the stuff in my bathroom. I use Fresh’s Creme Ancienne, which is made by monks or something, but you need to remortgage your house to be able to afford it! I love Dermalogica’s Multi-vitamin Power Recovery Mask, which makes you look like you’ve had eight hours’ sleep even if you haven’t. I put Sweet Almond Massage Base Oil in the bath and sleep with it on my hair. It’s cheap, natural and great for moisturising.

Have you always been blonde?
I was born blonde so, even though I became darker when I hit puberty, I feel a blonde at heart. I went brunette once but I didn’t get the same amount of attention so I quickly went back to being blonde.

Any other beauty secrets?
I love a good pick. I used to pay my brother to let me squeeze his blackheads – a pound a go. It’s gross, I know. I don’t get spots very often, but when I do, they stay for weeks because I keep going at them. I’m a serial picker. I hold my hands up.