The judge who sent Lindsay Lohan to jail has recused herself from the case following complaints from a prosecutor.
Court officials said Los Angeles Superior Court Judge Marsha Revel had improperly and privately contacted experts or people involved in the case.
These reportedly included staff at a rehabilitation facility which the judge chose as a place to send Lohan after her release from jail on 2 August.
Beverly Hills Superior Court Judge Elden Fox is now handling the case.
A clerk for Judge Revel told the Associated Press that she would not comment on the decision, which was made on Friday.
A spokeswoman for the Los Angeles County district attorney's office, Jane Robison, said there were several instances when the judge had communications and the prosecutor was not present or told afterwards.
In one example, she contacted the Morningside Recovery rehabilitation facility in Newport Beach, which was not on a list provided by court-appointed experts. She then selected Morningside as a place to send the Mean Girls actress.
Lohan's lawyer, Shawn Chapman Holley, eventually persuaded the judge to send Lohan to the Ronald Reagan UCLA Medical Center in Los Angeles.
The actress was released earlier this month from the women's jail in Lynwood, where she served less than two weeks of a 90-day sentence for violating her probation from a 2007 drunk-driving charge.
She was immediately sent by the court to the UCLA drug centre for a three-month rehabilitation programme.
Lohan had been on probation for almost three years after pleading guilty to misdemeanour drug charges and no contest to three driving charges.
She was ordered to complete a series of alcohol education courses. But she failed to do them on time and missed a number of meetings.
In May, an alcohol-monitoring bracelet was fitted after Lohan failed to attend a probation hearing. Her lawyers said she had been unable to fly back from the Cannes Film Festival in France after her passport was stolen.
Lohan's sentence has put several film projects on hold, including a role as Linda Lovelace in a biopic of the 1970s porn star.