Mischa Barton is trying to sell diet pills now or something

Mischa Barton's weight has yo-yoed since she shot to fame as Marissa Cooper on the O.C back in 2003.

But as she prepares for her new movie role, the actress, who has been displaying a fuller figure lately, has taken matters into her own hands.

Mischa, 28, has been taking a mushroom based supplement to manage her weight - and claims she's lost 4lbs in a week.

'As someone who naturally struggles with their weight, I wanted to find a supplement which worked in harmony with my body,' she said.

'I use Proactol XS as it has no side effects, is sourced naturally and lets me manage my weight safely. So far I’ve lost around 4lbs a week by taking the supplement.'

The tablets contain chitosan, a nondigestible dietary fibre made from the shells of crustaceans and sourced from mushrooms, which promises to neutralise calories from high fat content foods.

The chitosan forms a gel-like substance in the stomach, which mixes with the food and removes the fats and cholesterol from it, which is then passed through the body naturally.

Her latest campaign with Proactol XS comes at the same time as reports that Mischa's $7.1m home has been threatened with foreclosure as she owes $100,000 in back payments, according to documents.

The former O.C. starlet could lose her $7.1 million Beverly Hills estate if she doesn't pay the $100k in back mortgage payments she owes, according to TMZ.

Barton hit her Hollywood peak in the mid-2000s, starring as the sexy Marissa Cooper in 76 episodes of The O.C. After her 2007 D.U.I. arrest and the mental ward hold two years later, Mischa switched gears into fashion with her own line of handbags, cosmetics and clothes. Her London shop, Mischa's Place, sits on in the trendy Spitalfields Market on Brushfield Street.

After her flicker of fame began to fade following the cancellation The O.C. due to poor ratings, Mischa re-tooled her career, taking on several smaller roles on TV and in film.

Mischa has 17 projects in development, and seven films currently in production. She made 17 films since 2007, with none grossing more than $38 million.

Mischa, who told the British Metro newspaper that she wasn't as grateful for her involvement in the TV hit as she should be, will also head up a nationwide campaign to find Britain's most stylish vaper for e-cigarette brand VAPESTICK.