Hollywood star Lindsay Lohan faces the prospect of being put behind bars again after failing a court-ordered drug and alcohol screening test.
Lohan, 24, acknowledged the results on her Twitter page last night.
"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," she wrote in one of a series of posts late last night.
"Substance abuse is a disease, which unfortunately doesn't go away over night. I am working hard to overcome it," she wrote in another post.
The actress was sentenced to three months in jail followed by three months in rehab after violating probation stemming from drug and driving under the influence cases filed after two arrests in 2007. She ended up serving two weeks in jail and another 23 days in an inpatient rehab treatment at Ronald Reagan UCLA Medical Centre.
A person familiar with her case, who declined to be identified because of the sensitivity of the matter, confirmed the latest positive test results but declined to specify what substance was involved.
Los Angeles Superior Court Judge Elden S Fox had threatened Lohan with 30 days in jail for each probation violation.
A hearing will be conducted before Lohan could be returned to jail. Los Angeles County District Attorney spokeswoman Sandi Gibbons said no such hearing had been scheduled as yet.
The failed drug test was first reported by TMZ.com.
At a hearing last month, Fox ordered the actress to attend psychotherapy, drug and alcohol counselling as well as random drug and alcohol testing several times a week. Compliance would allow her to return to unsupervised probation in November.