Los Angeles, California (CNN) -- Actress Lindsay Lohan is expected to appear in court Friday after a judge revoked her probation earlier in the week.
Judge Elden Fox revoked Lohan's probation Monday and signed a bench warrant for her arrest, but the judge is holding it until a hearing at 8:30 a.m. Friday (11:30 a.m. ET), according to Los Angeles Superior Court spokesman Allan Parachini.
Lohan's supervised probation for a 2007 drunken driving conviction requires frequent drug tests. The judge warned her last month any failure could send her back to jail.
"Regrettably, I did in fact fail my most recent drug test and if I am asked, I am prepared to appear before judge Fox next week as a result," Lohan tweeted on September 17.
She spent 23 days in a court-ordered drug rehab program last month, which followed a 13-day jail stint imposed when a Los Angeles judge ruled that Lohan violated her probation.
Fox, who took over Lohan's case when she was released, imposed a new set of rules for her to follow until November. It included weekly counseling sessions for alcohol and drug rehabilitation, random drug tests and behavioral therapy.
"Substance abuse is a disease, which unfortunately doesn't go away overnight," Lohan tweeted. "I am working hard to overcome it and am taking positive steps."
Lohan tweeted that she was "doing what I must do to prevent any mishaps in the future."
"This was certainly a setback for me, but I am taking responsibility for my actions and I'm prepared to face the consequences," she tweeted.
Lohan made fun of her substance abuse troubles in a backstage skit broadcast during the MTV Video Music Awards earlier in September.
She appeared with show host Chelsea Handler, who was wearing an alcohol-detection bracelet like the one Lohan recently wore.
"Wake up, Handler, pull it together," Lohan said as she slammed Handler against a wall. "You're a menace. Do you think anyone will work with a drunk? Take it from me, they don't."
Lohan was arrested twice in 2007 on charges of driving under the influence, and in the second incident she was charged with cocaine possession.
The first arrest came after Lohan lost control of her Mercedes-Benz convertible and struck a curb in Beverly Hills.
Just two weeks after checking out of a Malibu drug and alcohol rehabilitation facility, she was arrested again in July 2007 after a woman called Santa Monica police, saying Lohan was trying to run her down with a car.
Lohan's acting career, which started at age 10 on a soap opera, took off on the big screen a year later, when she played identical twins in Disney's remake of "The Parent Trap."
CNN's Brittany Kaplan contributed to this report.