Stephen Fry addresses the "messy subject" of "drugs and dependency" in his latest autobiography, More Fool Me.
In the book - the third part of his life story - the presenter, writer and actor admits to having spent "an enormous amount of time and money on cocaine powder".
His first memoir, Moab Is My Washpot: An Autobiography, was released in 1997 and The Fry Chronicles in 2010.
"The only point of writing an autobiography, or so at least it seems to me, is to be honest," he told The Sunday Times.
"And in this book I have been utterly candid about a period of my life in which I spent an enormous amount of time and money on cocaine powder.
"I know how stupid that is, but I also know better people than me have found themselves on the same path."
He has spoken of his former addiction to the drug previously, saying that it helped calm his mind.
Fry – the president of mental health charity Mind – has suffered from manic depression and bi-polar disorder for years and has been an active voice in ensuring that the illness is more widely talked about and helping change any negative or wrong perceptions.
"There were 15 years of pretty chronic cocaine taking. In my most hyper frames of mind, I found it was a wonderful drug to take to calm me down," he said during Sky Arts programme In Confidence in June 2011.
"I tended to take it alone at home and play word games, mind spinning. I'd do very difficult crosswords, I would spend hours on these.
"I found it extremely easy to stop, but it took me a very long time to get to a position where I was ready to."
More Fool Me will be released on 25 September.Reuse content