Joan Collins was rushed to the hospital from the Vanity Fair Oscar party because her purple and lilac Georges Hobeika gown was too tight.
"I squeezed into it and resigned myself to not eating much at the Vanity Fair Oscars bash," she says of the gown.
PHOTOS: Backstage at Oscars 2011 - what you didn't see on TV
But at about 10 p.m., "I started to feel dizzy," she recalls in a diary for the UK Daily Mail. She and husband Percy Gibson "walked outside to get some fresh air."
"Next thing I knew, I was surrounded by some rather attractive firefighters who were asking me questions such as: ‘What's your name?' (as if they didn't know) and ‘How old are you?' (which I refused to answer)," wrote Collins, who is 77.
"Apparently, I had fainted in Percy's arms and he, in a panic, had asked security to call an ambulance -- which was roomier than Jackie's limo and, thanks to the sirens, much swifter in Hollywood traffic," she went on. "Not quite how I had expected to end this glamorous night!"
PHOTOS: Oscars 2011 party photos
"Nevertheless I put myself in the care of professionals at the hospital's Emergency Room," added Collins. "There, after an hour of tests, the doctors discharged me with stern admonishments not to wear such tight dresses — and to eat in future if I was expected to last the pace at the fabulous Vanity Fair party."
The Oscar winner told the New York Post Tuesday, "The truth was, I made the wrong decision to wear a very tight dress, and had something rather like a Victorian swoon. The good news is, I am in good health and feel fine today."