Mischa Barton has been sentenced to three years of unsupervised probation after pleading no contest to driving under the influence (DUI).

The former 'O.C.' actress - who was arrested for drunk driving last December - was also ordered to complete a three-month alcohol-education class and pay a fine of approximately $2,000 at a Los Angeles court Wednesday.

As part of the plea deal, which spared Mischa any jail time, prosecutors also dismissed a separate marijuana possession charge and reduced a charge of driving without a license to an infraction.

The 22-year-old star was not present at the Beverly Hills hearing, and her lawyer Anthony V. Salerno entered her plea on her behalf.

In a statement released after the hearing, Salerno said: "Ms. Barton understands the seriousness of this situation and assumes full responsibility for her actions. She and I are grateful to the Court and the District Attorney's Office for the prompt and respectful resolution of the case."

Mischa was arrested on December 27 after police spotted her weaving between two lanes of traffic and failing to signal. She spent seven hours in jail before being released on $10,000 bail.

Speaking about her arrest in January, Mischa admitted full responsibility, saying: "I'm really disappointed in myself. I don't know what to say about it, except that I'm not perfect, and I just don't ever intend to do something this stupid again."

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