Hollywood beauty Mischa Barton has hired a personal trainer in a bid to clean up her act following her drink-driving conviction.

The 22-year-old former The O.c. star was recently pictured relaxing on a beach in Los Angeles - but she has now hired a trainer to raise her fitness levels.

She says, "I never had a workout regime, but I have now hired a personal trainer because I feel my energy level is better when I work out."

Last week, Barton was sentenced to three years unsupervised probation after pleading no contest to charges of Dui, possession of marijuana and driving without a licence in February, following an arrest in West Hollywood in December.