Lindsay Lohan has blamed collapsing in a hotel room last week on exhaustion.
The actress went on Twitter to say she had been working too hard while filming a new TV movie in Los Angeles.
She said: "Note to self: After working 85 hours in four days, and being up all night shooting, be very aware that you might pass out from exhaustion and seven paramedics might show up at your door."
The 25-year-old's spokesman denied she had been taken to hospital.
Steve Honig said the star had been treated for exhaustion and dehydration.
In a statement Lohan's spokesman said the actress had been taking a nap and that producers called paramedics out of concern when she did not come out of her room on Friday morning (15 June).
Lindsay Lohan joked on Twitter about the ambulance workers sent to check on her.
"Hopefully they're cute," she said. "Otherwise it would be a real let down."
She had been working on a television movie about the love affair between actors Elizabeth Taylor and Richard Burton when she collapsed.
Lohan has struggled with drug and alcohol addiction in the past and was released from five years of formal probation in March over a 2007 drink-driving case.
She appeared as herself in an episode of Glee broadcast this year.