Troubled Hollywood starlet Lindsay Lohan was sent back to jail Friday by a Los Angeles judge after failing a court-ordered drug test. The 'Mean Girls' star was ordered by Superior Court Judge Elden S. Fox to jail pending an Oct. 22 court hearing, meaning Lohan could spend nearly a month behind the bars. S. Fox ordered the actress back to jail and set no bail in a brief court hearing. A week ago, Lohan confirmed in a Twitter posting that she had failed a court- ordered drug test.'Regrettably, I did in fact fail my most recent drug test and if I am asked, I am prepared to appear before Judge Fox ... as a result,' she wrote. Lohan was tested positive for cocaine and methamphetamine, the celebrity website TMZ.COM reported. Lohan spent three weeks at a drug-rehabilitation program at Ronald Reagan UCLA Medical Center last month. She went into the rehab program after serving 13 days in jail for violating her probation. After her release from the rehabilitation program, Fox ordered Lohan to remain in Los Angeles, participate in psychotherapy counseling and chemical dependency sessions, in addition to 12- step meetings. She was also ordered to submit to random drug and alcohol testing no less than twice a week and attend behavioral therapy classes twice a week. The judge ordered last month that he be notified within 72 hours of any failed or missed drug tests by Lohan. The 24-year-old actress was sentenced to a day in jail and put under three years of probation in August 2007, when she pleaded no contest to two counts each of drunken driving and being under the influence of cocaine, and one count of reckless driving. The probation later was extended for a year after she missed some alcohol-education classes. 