Karl Lagerfeld deemed her a 'fashion role model for an entire generation' when presenting her with an "Icon of the Year" award in 2008. And her hugely successful handbag line and fashion store in London's Spitalfields are testament to her fashion credentials.
So HELLO! Online was delighted to have the opportunity to chat to style icon Mischa Barton and get some sartorial tips from the lady herself. And sitting down for a cup of tea with the star in one of London's most lavish hotels, the first thing that struck me was her beautiful doll-like features that had the entire room transfixed.
Not to mention her lovely, totally down-to-earth manner that instantly put me at ease as we got chatting about fashion tips for HELLO! Online readers. "Wear things the way that you feel the most comfortable," is, according to the 26-year-old, key advice for the fashionistas amongst you.
CLICK ON PHOTO FOR FULL GALLERY
"Make clothes an extension of your own personality – that's definitely how I see fashion," she said, adding: "Fit the trends to you, not the other way round. Find out what's popular this season and figure out how it can work for you."
The actress, who shot to fame in her role as Marissa on hit TV show The OC, was talking at the launch of her line of mobile phone accessories with Uunique London, revealing her brand new designs to fit the iPhone 5.
Wearing a gorgeous cream embellished maxidress, Mischa looked gorgeous as she talked us through the collection, which, emblazoned with her logo and featuring lots of pretty patterns, is cute, quirky and has the star written all over it. Speaking about her collaboration, the star said: "I love accessories and the thing about phone covers is that you can totally change them to match your outfit."
So is design where she can see her career heading? "No, as I'm still heavily involved in acting," she replied. "I have just wrapped on a film with Jason Statham and I'm going to start shooting another film in January.
Mischa models the Lotus by Uunique - at £189,000, it is the most expensive iPhone case in the world
"For me, it's about doing a mixture of the things I love. Design is something I find quite easy and I enjoy as something as an extension of my personality – I've always had a visual eye and I'm very picky about the way things look."
With filming, splitting her time between London and LA and opening her new store, Mischa has had "the busiest year".
So we're keen to find out how the super slim star manages to stay in such great shape. "I run a lot," she admits. "And I often do weight training, but running really is my favourite thing.
"I try to run every day. If I'm working I have to skip, but I love it. I can get a bit obsessed!"
And she has a healthy attitude towards food and dieting, revealing that: "I do like indulging in some things, but I really like healthy food.
"If I am in a place where I can get healthy food, I much prefer it. I tend to go for vegetarian and vegan foods."
Finally, we want to know whether living in both countries is tiring.
"It is exhausting, yes, and I rely a lot on Elizabeth Arden Eight Hour Cream as my skin gets so dehydrated with all the flying, but I love being able to live in both places.
"My sister is here in London, I have other family here and I love the culture. But on the other hand, I get the weather of LA and that is where the work is.
"I totally get the best of both worlds!"