Nicole Richie’s high-profile arrest for driving the wrong way on the freeway this week wasn’t the first time she was nabbed for driving under the influence. Richie pled guilty to DUI four years ago, and according to TMZ if she’s convicted of DUI again she’ll have to serve a mandatory five day jail sentence.

TMZ has found court documents which reveal that Richie pled no contest four years ago to driving under the influence. Under California law, if Richie is convicted of DUI as a result of Monday’s arrest, the judge must impose a jail sentence.

The law requires a mandatory sentence of five consecutive days in county jail as well as a one year license suspension for anyone twice-convicted of DUI. In addition, Richie would be ordered to attend an alcohol education program for a year-and-a-half, even if the second conviction is not alcohol-related.

As TMZ first reported, Richie admitted to CHP officers that she had taken Vicodin and smoked pot before driving the wrong way on a Burbank freeway. A field sobriety test revealed she was not under the influence of alcohol.

Although Richie was under the influence of non-alcoholic drugs, it might not matter in court. She was clearly impaired and should not have been driving. Maybe she can call up Michelle Rodriguez for some tips on how to get all her fellow inmates singing showtunes.

In Richie’s previous DUI offense in 2002 she blew a .12. and a .13, and the limit for impairment is .08. At that time she told officers that she had a shot of vodka. Her license was suspended for a year and she had three years probation. She got arrested again for driving with a suspended license and possession of heroin just six months after that.

During her latest DUI arrest, Richie said that she had only eaten french fries that day.