TORONTO • At one stage, guitar great Eric Clapton was spending about US$16,000 a week on heroin in the 1970s. He was also addicted to alcohol - until the death of his son provided a wake-up call.
These details about the life of the British icon are revealed in a documentary that does not attempt to whitewash the darker moments, even though it is directed by his long-time friend, film-maker Lili Fini Zanuck.
Zanuck, who has known the musician for 25 years, directed Eric Clapton: Life In 12 Bars.
It follows the life of the 72-year- old guitarist from childhood to international stardom, through his struggle with drugs and alcohol and the 1991 death of his four-year-old son.
"To watch myself going through that was not easy," Clapton told reporters on Monday at the Toronto International Film Festival, where the movie made its debut.
"Right up until the time I stopped drinking, everything I said was complete blather," he added, to laughter from the audience.
"I haven't had a drink for a long time. And for the first 10 years of that period, a lot of my thinking changed. It was then and after I had my children, my daughter and my son, that... I had a responsibility I had to deal with."
In his 2007 autobiography, Clapton described a 20-year drug and alcohol addiction.
The death of his son Conor, in a fall from a New York high-rise apartment, was the trigger to sobriety.
The musician, who is a producer on the film, spoke about his struggles with having his life documented on screen and doing interviews with Zanuck in a film that does not shy away from examining his faults.
"I do not like having my picture taken. I do not like talking to journalists. I love to play music," he said.
Zanuck, who as producer won a Best Picture Oscar for 1989's comedy drama Driving Miss Daisy, said Clapton did not second-guess the responsibility he gave her in telling his story.
"For me, the movie is about redemption - personal redemption, not necessarily what society thinks," she said.
"No one got him out of despair, he did it himself," she added.
With hits such as Cocaine (1977) and Layla (1992), Clapton has won 17 Grammy Awards.
He was inducted into the Rock and Roll Hall of Fame in 2000.
He was ranked No. 2 on Rolling Stone magazine's 2015 list of 100 greatest guitarists of all time, behind Jimi Hendrix.
Eric Clapton: Life In 12 Bars will be released in North American theatres later this year and air on premium cable channel Showtime in February.
Clapton's plug for the documentary? "From all of that mess, I can still become a reasonably well-behaved human being, with some responsibility."
Not that the challenge has come as easily for him as playing the guitar. He said: "To consider what my behaviour does to other people is still a kind of difficult thing for me to comprehend, but it's getting better."