'The Hills' star Stephanie Pratt pleaded not guilty to a misdemeanor DUI charge Friday, but will enter a 30-day residential rehab center to tackle her problem.

Pratt was pulled over on Oct. 18 after leaving a birthday party for Holly Montag, her brother's sister-in-law. TMZ reported at the time that Pratt's two breathalyzer tests registered just above the legal limit of .08. She was arrested and held on bail.