Lindsay Lohan's new lawyer has quit for unknown reasons just a day before the Mean Girls star is due to go to jail.

Robert Shapiro, who formerly represented O.J. Simpson, was expected to represent the 24-year-old actress Tuesday in court ahead of her scheduled prison term.

The lawyer said last week he would only represent her if she agreed to certain conditions.

"I have agreed to represent Ms. Lohan on the condition she complies with all of the terms of her probation, including a requirement of jail time that was imposed by Judge Marsha Revel," he said.

The troubled star then entered sober living facility Pickford Lofts founded by Shapiro.

The lawyer told Judge Marsha Revel he was no longer representing Lohan yesterday.

Ahead of her prison sentence, Lindsay, meanwhile, has shown her humorous side by revealing her unfamiliarity with the term "bookings" on Twitter.

"the only "bookings" that i'm familiar with are Disney Films, never thought that i'd be "booking" into Jail... eeeks," her Twitter post said.