We're sitting in a busy restaurant at The Berkeley hotel in Knightsbridge, London. Mischa has a cold, probably due to her travel schedule – she's just flown in from Barcelona, where she's been promoting the Spanish release of Closing the Ring with the film's director, Sir Richard Attenborough.
SEE MISCHA'S GORGEOUS MARIE CLAIRE PHOTOS HERE
Mischa Barton is famous. Maybe you've asked yourself why a 22-year-old actress who made her name in an American teen soap opera is so famous, why she can command magazine covers on either side of the Atlantic and beyond. The reason is simple: few other young actresses of her generation have profited - and often suffered - quite so much from the internet explosion and the exposure.
'You know,' she says in this surprisingly husky voice, betraying her roots (part west London, part New York, and nothing like the LA vowels you'd imagine), 'People label me, but I don't care.'
The gossip websites have a love-hate relationship with Mischa Barton. Rarely a day goes by without a celeb blog passing comment on her fashion, or monitoring her weight.
Mischa doesn't read her press but everything gets filtered through eventually.
'I'm not really sure what people's preconceived notions are. I don't look at the gossip websites – it's unhealthy and I think it's a large part of what drives people in LA crazy. I'm an actress, I'm in this to find the next great project. The fact is, I'm having a real life and being a normal human being.'
When asked whether she was surprised at the press attention surrounding her arrest [for DUI] she laughs, 'I didn't know people cared.' The case is still pending at the time of our interview (Barton has since been sentenced to three years unsupervised probation after pleading 'no contest' to drink-driving), so she is limited in how much she can say – but her regret appears genuine.
'It was a low point in my life. The truth of the matter is, I was being irresponsible to begin with – I moved to LA and never got a licence,' she explains. 'I don't know, it was just an awful low for me. I apologized - and you have to just hope that that's enough. People make mistakes, you know?'
The OC, billed as the new Beverly Hills 90210, ran for a total of four seasons and was broadcast in over 50 countries around the world. Mischa Barton was 16 when she joined the show, 20 when she left. She'd had a successful career in theatre and film prior to the show.
She has fond memories of The OC, but will only return to television,
'when I understand it better. Because I didn't understand it. When you're 16, you don't know what the hell you're getting into. LA was a shock to the system.'
Mischa Barton is undoubtedly an actress of true potential, yet you can’t help but wonder if, ultimately, it will be she or the internet gossipmongers who decide her future. And that depends on whether Mischa Barton is prepared to change enough to relinquish the kind of fame that has made her famous. Let's hope she makes the right decisions.
This is an edited version of the full interview, which features in Marie Claire's bumper 20th birthday September issue, out now.