Actress Lindsay Lohan has revealed she has entered a residential treatment centre in the US.
Lohan recently starred in Altman's A Prairie Home Companion
"I have made a proactive decision to take care of my personal health," she said in a statement.
"I appreciate your well wishes and ask that you please respect my privacy at this time," she added.
The 20-year-old star of films such as Mean Girls and The Parent Trap admitted in December that she had been attending Alcoholics Anonymous meetings.
Lohan's spokeswoman would not say where the centre was located or what the actress was being treated for.
Lohan's frequent partying and drunken exits from nightclubs were a fixture of tabloid newspapers last year.
In July, Morgan Creek Productions chief executive James G Robinson sent a letter to the actress rebuking her for arriving late on set for the film Georgia Rule, suggesting "heavy partying" was to blame.
"You have acted like a spoiled child, alienated many of your co-workers and endangered the quality of this picture," he was quoted as saying in the letter.
The actress admitted that she became worried by her portrayal in the press.
"I was like, 'I don't want to be written about at these clubs with these people'," she told People magazine last year.
"I work, I act, I have a living. That's what I do every day. I work every single day."
Lohan has most recently been seen in the film Bobby, which centres on the assassination of Senator Robert Kennedy in Los Angeles in June 1968.