Tom Hardy is sitting opposite me in a Los Angeles hotel suite, which is a minor miracle considering what he has to go through to be allowed into the United States.
In order to obtain a visa to work in Hollywood, the talented British actor, whom critics are comparing to a young Marlon Brando, has to present himself to the US Embassy in London to assure the authorities he regrets his past behaviour and is now reformed.
"If you look at the reasons why they won't let me into the country you'll see how far I've come," he says. "Between the ages of 12 and 19 I was a naughty boy, so the bottom line is I have to go and apologise and fill a certain quota of boxes to get my visa, be allowed into America, work and pay my taxes."
"Naughty boy" is something of an understatement. Expelled from boarding school for stealing, he developed an alcohol and drug abuse problem as a teenager, periodically spent nights in jail for disorderly conduct and was once arrested for stealing a car and gun possession. He avoided prison, he says, only because his companion and co-conspirator was the son of a British diplomat. He finally checked himself into rehab and cleaned himself up in 2003 after, he says, he collapsed on Soho's Old Compton Street.
Now 34 and a highly regarded actor after roles in RocknRolla; Inception; Warrior; Tinker, Tailor, Soldier Spy; and in the third outing of the rebooted Batman film series, The Dark Knight Rises, as the ferocious, chemically enhanced muscleman Bane, he talks openly and unabashedly about his chequered past.
"I was a lot naughty," he says. "I hit a brick wall of behaviour. There were the options of institution, death, prison or insanity, and I could tick the boxes on three of those so I was very lucky that I had a moment of clarity. Something happened and I did something so heinous that I saw myself and I didn't want to be that person. So from that moment on I ceased to be that person and started to grow towards the person I wanted to be. I never want to go back to that again. It's craziness."
His romantic life, too, was wild and unpredictable. "I was a serial boyfriend," he says. "I've never been on my own. I'm an only child and I can't live without company, but going out with me and being my partner is a struggle because I demand a lot of attention and I'm quite needy."
Hardy is an unusually intense and complex character who refuses to dodge embarrassing issues and talks with sometimes devastating honesty - and in occasionally convoluted sentences - about subjects most actors would avoid. He thinks deeply about spiritual issues, is a devotee of homeopathy and holistic medicine, and acknowledges that he attends regular therapy and counselling sessions, something few stars would admit.
"I continue to go through group counselling, therapy and anything necessary to keep my feet on the ground and be in a quality relationship and to right-size myself as a boy turning into a man and in a relationship with a woman," says Hardy, who lives in London with his fiancée, the actress Charlotte Riley, and has a 3-year-old son, Louis, with a former girlfriend.
"I'll do anything I have to do to clean up my act and be a better father and a better husband and boyfriend. That sounds really worthy, doesn't it?" he says with a sudden laugh. "But I have to do it.
"I've been to all kinds of different rooms in my life, so the fight that I have on a constant basis is just to try and better myself and not regress and to find a new way forward in a healthier manner. My dark places are very specific; people live in violence, abject poverty and crime and I have no idea of the depths of their despair and suffering; my suffering on a scale of one to 10 is probably one, but it's my pain and coming from where I come from. I don't pretend to know anything about great suffering. I've had a bit of a rough life but it wasn't that bad and I'm very lucky."
Tattoos peek out from beneath the sleeves of his red T-shirt and cover most of his body, which, he says with a grin, could be a problem if he ever wants to portray Moses or King Lear on stage. "I got the first one on my arm when I was 15 and the second on my back when I was 17 and they started to spread," he says. "Each tattoo is a period of time in my life I've been through or a friend I've lost or made - my son... my mother... I mark myself with everything I've been through at the end of every episode. When I went to drama school they used to tell me I wouldn't get work if I had a tattoo, but I'm working so I get another tattoo every time I do a job."
We are talking because after a series of tough guy roles he has taken the plunge into the well-paid realm of Hollywood romantic comedies and is co-starring with Chris Pine and Reese Witherspoon in This Means War, a frothy and amusing tale of two deadly CIA operatives who fall for the same woman and use their skills and high-tech gadgetry against each other.
Pine describes his co-star as "infuriatingly talented," adding: "Tom is super-charismatic and handsome as all hell and he brings a complicated nature and English sensibility to his role."
Hardy's good looks are currently hidden behind a bushy beard he has grown in readiness for the title role in the much-delayed Mad Max sequel, Mad Max 4: Fury Road, but first he will be going to Siberia with the Discovery Channel for a documentary on the coldest road in the world.
"I thought it would be good experience for the wastelands of Mad Max and it appeals to the boy in me who wants to go out and explore and be intrepid," he says with another laugh. He is donating his fee to charity.
The only child of the writer Edward "Chips" Hardy and his artist wife, Anne, Hardy grew up in East Sheen, west London. He started drinking at 13 and became a drug and alcohol addict, but at 19 he entered and won a television contest, Find Me a Supermodel, and briefly had a modelling contract.
He was expelled from the Richmond College for the Performing Arts and studied Method acting at the Drama Centre in central London. But he cut his studies short when he landed a role in the TV miniseries Band of Brothers followed by film roles in Black Hawk Down and Star Trek: Nemesis.
His substance abuse contributed to the breakdown of his marriage to Sarah Ward, and with his parents' help he checked himself into rehab and submitted to a regimen of psychotherapy.
Finally clean and sober, he landed a number of television and film roles, including the Earl of Leicester in the BBC miniseries The Virgin Queen and Heathcliff in a dark television update of Wuthering Heights.
He says: "I wanted my dad to be proud of me and I fell into acting because there wasn't anything else I could do and in it I found a discipline that I wanted to keep coming back to, that I love and I learn about every day."
A supporting role as a sleazy street thug in the crime thriller w Delta z was the start of a run of gritty roles in which he brought texture and depth to unsavoury characters: Bill Sikes in the BBC version of Oliver Twist, a gay gangster in Guy Ritchie's RocknRolla and then his visceral portrayal of the notoriously violent convict Charles Bronson in Bronson, which won him critical acclaim and the British Independent Film Award for best actor.
"Nobody paid any attention career-wise to me in America until Bronson," he says, "and it gave me a calling card and passage into America, where I've always wanted to work."
His first US role was as a tough young bootlegger in the yet-to-be-released prohibition-era drama The Wettest County in the World, on which he reportedly clashed off-screen with his co-star, Shia LaBeouf, another victim of a troubled childhood. He has been quoted as saying that LaBeouf knocked him out although he now says: "We were just playing around. For the movie Shia went from being quite a gentle young man into a very rough, heavy-handed individual and I'd just done Warrior and we were always play fighting and mucking around. So yeah, he gave me a bit of a slapping. He's a big boy."
This is a busy time for Hardy. He has forged a Hollywood deal with Warner Bros Pictures that allows him to produce and develop his own projects, and he has a television series written by his father that he hopes will air later this year. After his Siberia trip he will return to England for a six-week break before leaving for Namibia to begin work on the latest in the Mad Max franchise.
He tries hard to adapt his schedule to allow him to see his girlfriend and his son every three weeks or so. "I'm very much aware of being a Skype father, which is really sad," he says. "I love what I do but I love being a dad more, so if I can do what I do a bit quicker and make some more money I can go away for shorter times and have the ability to bring my family with me. But at the moment I have to do what I have to do.
"The plan is to just exist and live my life as fully as possible. I love acting and I love storytelling but when I die I want to be able to look back and know I've looked after my parents, I've taken care of my children and then I'll just disappear into dust with the epitaph: 'Here lies a decent man.'"
Then, perhaps thinking he is being too serious, he laughs abruptly and adds: "And he's still lying."
This Means War is playing in UAE cinemas now. The Dark Knight Rises is due here in August.
The Hardy file
BORN September 15, 1977, Hammersmith, west London
SCHOOLING Reed's School, Cobham, Surrey; Tower House School, East Sheen, west London; Richmond Drama School
FAMILY Son, Louis, age 3
FIRST JOB Male model
FIRST KISS Can't remember
CAN'T BE WITHOUT My son
LAST BOOK READ Scars of War by Shlomo Ben-Ami
LISTENING TO Talk radio and "loud obnoxious rap music"
BIGGEST REGRET Being a naughty boy
HERO Any soldier who fights for his country
SECRET PLEASURE Watching Fireman Sam (the Welsh animated children's television series)