*Nicole Richie’s probation on a drunken driving conviction was extended by one year Tuesday because she was unable to attend the required alcohol education classes.

Her lawyer, Shawn Chapman Holley, explained to the Los Angeles judge that Richie had a court-approved leave of absence from her classes so that she could raise her kids, Harlow, 2, and Sparrow, 9 months.

The 28-year-old remains on probation from her 2006 DUI, in which she was arrested after driving the wrong way on an L.A. freeway. The reality star later admitted to smoking marijuana and taking Vicodin before taking the wheel, and spent 82 minutes in jail.

She was also arrested in 2003 and charged with heroin possession and driving with a suspended license.

Richie’s probation was extended until March 2011, but the judge said she’d call off the probation if Richie finishes her classes earlier.