How I found my inner hippy

Leo Gregory made his name playing modern-day hooligans. But when he took the role of drug-addled 60s icon Brian Jones - mercurial genius of the Rolling Stones - it changed his life. He talks to Will Hodgkinson
Leo Gregory
From throwing stones to playing them ... Leo Gregory. Photograph: Linda Nylind

Brian Jones - the original self-proclaimed "leader" of the Rolling Stones - has been mythologised, deified and demonised in equal turns since his death in June 1969. The everactive Brian Jones fan club organises annual pilgrimages to their hero's birthplace, the not-quite-rock'n'roll town of Cheltenham, while a new generation of thatch-haired romantics emerge every few years to ape Jones's music, lifestyle and most importantly, dress sense. As Gered Mankowitz, chief photographer to the Jones-era Rolling Stones, has it: "I've met people who have taken out a second mortgage to buy a pair of Brian's old shoes."

Leo Gregory was not among their number when he landed the part of Jones in Stoned, Stephen Woolley's long-planned biopic on the final days of the original Byronic pop star. "I had never heard of him," admits Gregory. "When I read the script I kept thinking, did this guy really exist? How can there be such an original, multi-faceted, fucked-up guy who was the original Jimi Hendrix, Jim Morrison and Kurt Cobain, and neither myself nor any of my friends know who he is?"

Not only had Gregory never heard of Jones; the entire world that Jones came from was alien to him. "I could have named you maybe two songs by the Rolling Stones before I got the part," he says. "I grew up in the 1980s and 1990s, which were all about making money and rejecting the 1960s thing of letting it all hang out and being creative. The closest I got to Brian's world was when my mum stuck on a record by the Who."

Gregory had less than a month to prepare for shooting after he was offered the part. There were logistical problems; he had to get up on stage at Brixton Academy in south London with a guitar and look as though he knew what to do with it, only three weeks after picking one up for the first time. And there were character problems, too. Brian Jones was a complex man. He fathered a string of illegitimate children while still in his teens; he could be proficient on any musical instrument within days; and he had a prodigious appetite for drink and drugs that he was physically and mentally too weak to cope with. He had rock-star charisma, but came from solid middle-class stock. Keith Richards got along with him, but former Rolling Stones manager Andrew Loog Oldham wasn't so sure. In his autobiography he simply describes Jones as "a cunt". Gregory has drawn his own conclusions.

"He could be the most charming, eloquent, gregarious, peacock-like figure, and then in the blink of an eyelid he could turn into the biggest shit," he says. "He would take delight in pulling people to pieces. So I was trying to work out where that came from, and like most things it seemed to stem from childhood. He came from a 1950s world in which you speak when you're spoken to, and he was pushed to the periphery by his parents after his younger brother died. Then he gets a band together and it's cool, but that falls apart when Andrew Loog Oldham comes along. Throw in a bunch of drugs and a fragile mental state and you can see how things might go wrong."

And things certainly did go wrong. Stoned focuses on the last days of Brian Jones, when his future status in the Rolling Stones was hanging in the balance, the love of his life (Anita Pallenberg) had run off with Richards, and he was living in hermetic, drug-filled seclusion at his Sussex home with only a builder, the deeply conservative Frank Thorogood, and a fly-by-night girlfriend, Anna Wohlin, for company. The old rules of society had been overturned in Brian Jones's world, but nobody was quite sure about what the new ones were yet. Part of Gregory's job was to understand the vagaries of the swinging 60s as much as those of the character he was playing.

"I was trying to nail the 1960s," he says. "I was like, 'So Keith sleeps with Anita, and Brian doesn't mind, and everyone leaves their doors open and loves each other?' Nowadays Keith would get stabbed in the eye for looking at Anita. Whereas Brian's friends would sit around smoking pot and playing the flute, my friends would have been selling pot and going to prison. Brian was androgynous, but in a masculine way. Nowadays it's a case of, 'Are you gay or straight?' That 1960s culture of everyone just being themselves and doing their own thing was different from anything I knew."

Before the Jones role fell into his lap, Gregory was carving out a reputation as the ultimate hoodie, chiefly based on his role as a rampaging council estate teen in the 2002 TV drama Out of Control. Gregory spent his adolescence with his mother in Camberwell, Stockwell and Fulham, in south London, in a culture where expressing one's individuality was not an option. "I'd say that there was a coldness to my background. If you wanted to be different, you either had to have an army behind you or an army within you, because the reaction would always be, 'What do you mean 'different'? Who do you think you are?'"

After getting a taste of acting with some small television parts in childhood, Gregory had a brief spell at the income-assessed boarding school Christ's Hospital, currently famous for featuring in Channel 4's Rock School. He was expelled at the age of 15 for being "too 60s for them, shall we say". He returned to Camberwell, started working as a DJ, got involved with the urban music scene and made friends with Wandsworth's evertroubled collective, So Solid Crew.

"The Rolling Stones would play a concert in the 1960s and some girls threw knickers at them, but my friend Ashley [Asher D] would do a gig with So Solid Crew where two people got shot and he could never perform again. And I was doing next to nothing. So I asked myself, what's the one thing I could enjoy and make a life out of, and appreciate as an art form?"

The success of Out of Control resulted in Gregory being offered every hooligan part going. He took one of them in the football-firm film Green Street, but also went the other way, with a role in the Jewish romantic comedy Suzie Gold. The decadence and colourful promiscuity of Stoned is a world away from the harsh retribution of Out of Control, and Gregory has been changed by the experience of immersing himself into Jones's strange, brief life. "At first I thought it was just a great gig," he says. "It's turned out to be life-changing. It's changed the music I listen to, the way I dress, and the way I view people. I've realised that I was playing into society's hands when I looked at some long-haired guy as a freak. Now I think, let's get to know each other."

· Stoned is released on November 18.