But she'll have great-looking hair because the 22-year-old has just become the face of the newly relaunched Herbal Essences.
The new line up comprises ten sets of shampoo, conditioner and intensive mask, Mischa's favourite of which is Hello Hydration with coconut and orchid extracts.
"My hair’s fine and it can get a bit dry, so the fact that it boosts the moisture in my hair is great for me. I just love it," Mischa reports.
And the star has revealed she takes a casual approach to looking good.
“It can be fun and really exciting to dress up for a big event, especially something important - if it’s for a good cause or if it’s a really glamorous event like the Academy Awards. But for the most part I’m a bit more laid-back and like a more natural vibe,” she says.
“I think it’s cooler when girls look themselves, so I don’t fuss too much about the way I look – I really dress for me," Mischa continues. "I think it’s important as a girl that the way you dress and the way you look are for yourself and you’re not just trying to please other people all the time.”
Which is just as well, as the star admits that she doesn't always look like an A-lister.
“I definitely have bad hair days! My hair’s a bit unruly sometimes, so I condition it lots," Mischa says.
"I don’t actually mind messy hair; I quite like a ‘tousled’ look. My hair doesn’t dry completely straight. I don’t like it when it looks too perfect, so long as it feels great.”
Herbal Essences is available from most chemists and supermarkets nationwide, priced at £2.29 each for 250ml of shampoo and conditioner. Visit www.herbal-essences.co.uk for more info.