Lindsay Lohan could be facing the prospect of time behind bars after it was revealed the troubled actress may have violated specific instructions handed down to her by a judge.

Lohan, currently on probation for a DUI, was told she would have to attend once a week classes on alcohol education.

TMZ has reported that the school that the 23-year-old enrolled at has not reported the star missing. However, the school's rules say if a student is missing for more than three weeks then they report the absence.

It appears in Lohan's case that she always showed before the 21-day period elapsed. However, as the judge told her she had to turn up once a week, Lohan may face the music for not going the amount of times the judge said she would have to.

Lohan will find out her fate when she goes back to court on May 20 .