Mischa Barton leaving the zac posen show during New York fashion week. New York City, USA .

Former THE OC star Mischa Barton was forced to work on part of her personality when she realised stardom was making her 'vain and self-obsessed'.

The 20-year-old insists she has addressed her bulging ego, and believes actors need to stay grounded if they want to really connect with audiences.

She says, "I was becoming too high maintenance.

"Actors will start talking about themselves as if they're the most important people on Earth - and I was no different.

"We have to have a big belief in ourselves. For most of us it's all about'me, me, me'. It's a mad business.

"You play so many characters, and have to try to almost become them, that the self-absorption can take over your life.

"The moment you have success, people give you things, they make a fuss and try to make your life easy. And the younger you are, the worse it can become.

"At times I've thought to myself, 'I deserve this.' But I don't deserve anything at all. I'm 20 for goodness sake." (Source: WENN)