Stephen Fry has spoken in depth for the first time about his battle with manic depression.
The actor and comedian attempted suicide after walking out of the West End play Cell Mates in 1995.
He recounts his darkest days in a new BBC2 programme, The Secret Life of the Manic Depressive.
"Eleven years ago in the early hours of the morning I came down from my flat in central London," he tells the documentary.
"I went into my garage, sealed the door with a duvet I'd brought and got into my car.
"I sat there for at least, I think, two hours in the car, my hands on the ignition key. It was a suicide attempt, not a cry for help."
But Fry did not go through with it - instead he fled the country, a disappearance which made headlines.
He explained: "I drove to the South Coast and took a ferry to Europe. I just knew I couldn't be at home. I really believed I would never come back to England. I couldn't meet the gaze of anyone I knew.
"But after a week I secretly returned to England, to this hospital, and to a doctor telling me I'm bipolar.
"I'd never heard the word before, but for the first time at the age of 37 I had a diagnosis that explains the massive highs and miserable lows I've lived with all my life.
"There's no doubt that I do have extremes of moods that are greater than just about anybody else I know."
In the documentary, to be screened this autumn, Fry interviews other celebrities who suffer from manic depression or bipolar disorder.
Star Wars actress Carrie Fisher, Hollywood star Richard Dreyfus and British comedian Tony Slattery are among them.
BBC2 controller Roly Keating said: "Stephen talks about his own experiences with incredible candour and bravery.
"I think he felt he could use his prominence to make a difference. It is a totally misunderstood condition."