Mischa Barton has been ordered to lose 10lbs for her role as a model on the new CW series The Beautiful Life.

A source tells Britain’s Star Magazine that the actress – who was recently released from hospital after being placed under involuntary psychiatric care – was “shocked to tears” when she was told to slim down for her first TV gig since leaving the FOX hit The O.C. several years ago.

“She knows that means they are calling her fat behind her back. She knows she is heavier than she needs to be but to hear it like that… it really shook her. How can Mischa play a model when she’s looking so heavy?” says a tipster

“She’s broken down in tears more than once before shooting. It’s a lot of pressure for someone who is just out of hospital.”

Even before being committed to the psychiatric ward, the ballooning actress’ weight had been yo-yoing for months, reportedly due to drug and alcohol abuse.

“Mischa has a very addictive personality,” says her pal, actress Suzanne Coppin. “She can become addicted to just about anything — booze, cigarettes, food and fame. And when times are tough for her she really stuffs her feelings with food.”

Despite the upsetting news, Mischa is determined to get back in shape as quickly as possible.

The source added: “She’s always been able to lose weight fast. Everyone knows she’s been struggling, so people are just really rooting for her.”

The Beautiful Life premieres next month on The CW.