British actor and comedian Stephen Fry says his depression may one day lead him to commit suicide and that bipolar disorder should not be dismissed as a "celebrity designer accessory".

Fry, 53, has long spoken publicly about his battle with cyclothymic disorder, a form of bipolar disorder, including in his documentary series Secret Life of The Manic Depressive.

In an interview aired in Britain, Fry expressed his frustration that his condition was sometimes described as "bipolar light". 

"It's a morbid condition and any doctor will tell you it's one of the most serious morbid conditions at present in Britain," he told the Sky Arts interview program In Confidence.

"The fact that I'm lucky enough not to have it so seriously doesn't mean I won't one day kill myself. I may well."

He joked that many people do not talk about their mental health issues, in the same way no one would show off a case of genital warts.

"We'll take your word that you've got them, but must you really show them to anybody?

"Similarly with my mental disorders, why would anybody want to see [them]?"

But he said it was worth speaking out for the sake of others who might turn to alcohol and drugs to control their moods.

"I know how easy it is to think that it must be a celebrity designer accessory problem, in the same way that homosexuality is seen as one because only people like me talk about it.

"Naturally someone who works in an office is not going to talk about their mental instability because they'll either get teased bullied or fired.

"That's the problem with it, the stigma of it is enormous."

In excerpts of the interview published in The Daily Mail, Fry also spoke about the "exhausting" demands of fame.

"You resort to not travelling on the Tube or walking round the street any more and going in a big car with a driver.

"And people think, 'Oh, he thinks he's so grand, doesn't he?' Well, no. I'd rather walk, but sometimes I just can't.

"I feel I would love to close down for a number of years in some way and just be in the country making pork pies and chutneys and never have to poke my head out of the parapet.

- Sydney Morning Herald