VENTURA, Calif. — A defense lawyer for Britney Spears appeared before a California judge on Monday and pleaded guilty to a lesser charge stemming from her arrest on suspicion of driving under the influence in March.

Spears admitted to a vehicle code violation known in California as a "wet reckless" and was sentenced to 12 months probation and one day of jail, credited as time served, by Ventura County Commissioner Matthew Nemerson.

Spears, 44, was pulled over on March 4 for allegedly driving under the influence, though authorities have not yet disclosed what substance she might have been using just before her arrest.

The "Toxic" singer has since checked into a treatment facility after several people close to her encouraged her to do so, a source familiar with the situation told NBC News.

Ahead of her Monday court appearance, Spears posted one picture and a video clip to her Instagram on Sunday.

The picture was of about four dozen floral design tea cups and the video showed her dancing in a short sparkling dress.

Sossy Dombourian reported from Ventura, California, and David K. Li in New York City,