Lindsay Lohan has checked into a rehab facility, but it remains unclear whether a judge will accept her choice.
Attorney Mark Jay Heller told Los Angeles Superior Court Judge James R Dabney that the actress had checked into a facility, but it is not the one prosecutors had signed off on.
Santa Monica City Attorney Terry White told Judge Dabney he had not had time to vet the centre, and needed longer to do so, reports Sky News.
Judge Dabney ruled Lohan should remain in the current programme for now, and gave prosecutors until May 10 to decide whether they approve the facility.
Leaving a Los Angeles-area court on Thursday morning, Mr Heller told reporters he could not comment on the situation.
Celebrity website TMZ reported that Lohan decided at the last minute not to enrol in the Seafield Centre in Westhampton Beach, New York - a facility that prosecutors had decided met the conditions of a plea agreement reached in March.
Instead, she reportedly entered Morningside Recovery in Newport Beach, California, early on Thursday.
Lohan pleaded no contest in March to reckless driving and lying to police after a June 2012 car accident in Santa Monica.
As part of the deal the actress was ordered to serve 90 days in a locked, residential rehab facility, checking in no later than May 2.
She must also complete 30 days of community work and attend therapy sessions for 18 months.
In April she told late-night television host David Letterman she viewed the rehab sentence as "a blessing ... and not a curse".
She said: "I think, to be honest, I'm the happiest when I'm working and the healthiest, and I think this an opportunity for me to, you know, focus on what I love in life. And I don't think it's a bad thing."
The former child star has been jailed or placed under house arrest for short periods a number of times since 2007, including three times in 2011.