Richie says she has learned her lesson

Nicole Richie has promised that being sentenced to jail time has encouraged her to change her ways.

The socialite was arrested in December last year when she was spotted driving the wrong way on a California highway. She told officers that she had smoked marijuana and taken painkiller Vicodin before driving.

Richie was ordered to report to jail by September 28 when she appeared in court last week. She must complete a 4-day stint in prison, as well as pay a $2,048 fine and complete a 21-day alcohol education course.

"I could have killed someone - I think this was a blessing in disguise," Richie told OK! magazine. "This year has been full of lessons learned and soul-searching and realising I'm an adult. It's time to take responsibility and not take the easy way out."

Nicole confirmed that she is "definitely" over her addictions, adding: "I never want to make a mistake like that again. I never want to possibly take another life in my hands. My life is clearly going to slow down."