Paul Farmer, the chief executive of mental health charity MIND, says Stephen Fry is helping to "sweep away the stigma surrounding mental health".
He said: "Stephen Fry, our president, has been extremely open and honest about his own mental health and the depths of despair he has experienced, and we know just from the response we've had in the last 24 hours how important that is to thousands of people who now feel that they're not alone."
There are around 6,000 people who take their own lives in this country every year.
For help and advice about mental health issues visit the MIND website.
Stephen Fry has joined the campaign against cuts to North Norfolk's ambulance service.Mr Fry, who grew up in Norfolk and is a director of Norwich City Football Club, has been tweeting about the petition against the cuts to his five million followers.