What if I didn't go into work today and just drank whisky for breakfast and went into town without getting dressed?

I think there is something quite appealing about that."

Ewen Bremner may have found fame playing a hellraiser in Trainspotting all those years ago, but he's an unlikely party animal these days. Quiet, unassuming, friendly, thoughtful, and not a man given to rash outbursts or the kind of crazy exploits likely to have the tabloids sniffing around, the 42-year-old is just happy to be at home in Edinburgh. "It is gorgeous and sunny, as always," he laughs. "I really love it, but my work is usually somewhere else."

So why is he considering taking his breakfast on the rocks and wandering the streets of his home town in the altogether? In a busy year, of which more later, the actor's latest role sees him joining Rev's Tom Hollander in a BBC2 biopic of Dylan Thomas, showing the wild later years, and eventual tragic early death aged 39 of the Welsh poet. We are talking about the archetypal figure of the flawed genius - whether that be John Lennon or George Best, Janis Joplin or Dylan Thomas - and why they remain so compelling, even if these days the flaws, the addictions, the abusive relationships are more likely to be publicly known than in the past.

"It is really romanticised, you come across these characters all the time in our culture, and I guess part of it is that we recognise that abandon and recklessness that we are all too inhibited to embrace or to indulge in," says Bremner. "And when we do indulge in it, we are chastised for it. Perhaps these flawed genius characters represent the fearless abandon that we are covetous of. We are not exactly jealous, but we are excited by people who are brave enough to do it. Fearlessness is really attractive and frightening at the same time."

In the one-off, 90-minute drama, which airs on BBC2 later this month, Bremner, as is so often the way, has a pivotal supporting role. He plays John Malcolm Brinnin, the poet, academic and well-connected literary high flier (a friend to Truman Capote and Tennessee Williams, among others) who brought the troubled Welsh wordsmith to the US for a series of high profile readings more akin to rock 'n' roll concerts than poetry recitals.

Filmed in just three weeks, the drama centres around Thomas's battle with the bottle, and his increasingly fractured marriage to Caitlin (Essie Davis) and friendship with Brinnin, whose own best-known work remains Dylan Thomas In America, an account of touring with his friend and idol which was the basis for A Poet In New York.

"This was pre-Beatles, and Dylan Thomas was arriving in America to hordes of screaming adoring fans, so excited that he was arriving," says Bremner. "But then the people who did come into contact with him were often disturbed by the experience in one way or another.

"From my point of view, it is a story about these passionate and destructive emotional relationships more than the actual people themselves. It is a good portrait of difficult human messes that people can get into. I didn't know anything about Brinnin before this, and precious little about Dylan Thomas, so I had a good time finding out what they were about. Brinnin cared about what was going on culturally, and was desperate to share the magic of this amazing man with America and give the culture a kick, you know?

"At the beginning he was blinded by Thomas's brilliance, but he did accept that this genius was also dangerous to be around. Ultimately, all of Dylan Thomas's relationships were abusive."

Not for the first time, Bremner was asked to adopt an American accent for the part. What made it more difficult this time was that the entire film was shot in Cardiff and around Thomas's isolated cottage by the beach in the fishing village of Laugharne.

"I have done it a lot, but it always feels a bit gnarly, I always feel a bit on edge about it," says Bremner of his US accent.

"You always feel on the verge of making a real mess and destroying the entire production! It is hard to relax, especially on such a short production. On a big American production, we might have been shooting for months, so eventually I might stop worrying."

It is also not the first time Bremner has featured in a film or TV drama that has, as its central focus, addiction. The first time we met was during the filming of the 2012 BBC1 political thriller, Blackout, in which Christopher Eccleston played a rising politician who believed he'd committed a murder while in an alcohol stupor.

That time, Bremner had sat opposite me, in a cavernous Manchester office building talking happily and openly about life, acting and everything - while shuffling in his seat so awkwardly that it was impossible not to get flashbacks to the iconic interview scene in Trainspotting, one of the most successful movies dealing with addiction.

"I did that film a long time ago, but it was considered by the people producing it and funding it that it was definitely going to be a flop - because no film about heroin addicts ever made a dime!" recalls Bremner.

"And the reason they were funding it was not even for that film in itself, they wanted to cement a relationship with the filmmakers for their next film, which was going to be a commercial blockbuster. That was the version of events I heard, anyway. But they found a way to go right into that world and make it compelling."

Playing Spud established Bremner as a screen actor, and remains, he admits - without sounding weary or frustrated about it, even though it was 18 years ago - the role for which he is most recognised. The path he has followed since has been anything but straightforward. The title role in Harmony Korine's Julien Donkey Boy, alongside Chloe Sevigny and Werner Herzog in an unsettling, uncompromising account of love and schizophrenia that split critics in 1999 showed a willingness to experiment and proved his aptitude for accents.

Pearl Harbor and Black Hawk Down, both released in 2001, were big budget, box office dynamite, in which Bremner fitted seamlessly into ensemble casts alongside some of the biggest names in Hollywood. Alien Vs Predator, three years later, was another to smash through the $100million mark.

Bremner has continued to work with some of the finest writers and directors - appearing twice for Woody Allen, in Match Point and You Will Meet A Tall Dark Stranger - and says he's finally starting to understand the "black art" of casting.

This newly acquired understanding is clearly working. For Bremner has never been busier - although he still finds time for occasional low budget films, and to show off some quirky oddball dance moves in a video for Trouble Not, one of the songs he has recorded as ExitMan. "Yes, that is supposedly me," he jokes, when I commend him on his skills. "It looks like me, but I'm not convinced! I wouldn't go so far as to say I'm a rock 'n' roller, I am really well behaved, early to bed. But maybe I have a few moves. If you say so!"

Back to the acting, he says: "I'm at an age now where I have finally started getting grown up parts," he says. "Most of the work I'm known for has been a bit of more youthful, but I'm not that youthful any more.

"I used to mostly get very empathetic characters or victims or these comic rascals, now I play responsible fathers, hard-ass political animals and this guy, Brinnin, who is a major player in the quite rarefied circles of the American poetry scene.

"Acting is a precarious business. I have had periods where I felt like I couldn't get arrested, but you have to see it as a long game. This is the only kind of work I have ever done, and I keep getting asked to do different kinds of parts, so I can't really complain. I do all right, you know?"

This year, we've already seen Bremner reprising his role as MI5 schemer-turned-journalist Rollo Maverley from David Hare's 2011 political thriller Page Eight, alongside Bill Nighy in Turks & Caicos and Salting The Battlefield. After confirming that Get Santa, which he shot this winter alongside Jim Broadbent will come out "around Christmas" - before realising he's stating the bleeding obvious and spluttering "I would hope so, anyway" - he mentions an international blockbuster set to be unleased this summer.

"I'm really excited to see Snowpiercer, which is a Korean sci-fi movie, based on a French graphic novel, with Tilda Swinton, John Hurt, Ed Harris and Chris Evans, from Captain America, as the main guy," he says. "It is a futuristic film set on a train, about the last people alive on earth. It's already getting amazing word of mouth."

Bremner's next job takes him to Sydney to play Reverend Johnson in Jimmy McGovern's seven-part epic for BBC2 about the first arrivals at the newly established British penal colony in Australia. "I am just sorting out the last stuff before I vanish," he says, before describing the series as "very dramatic, desperate, dark and juicy.

"Jimmy McGovern is very much obsessed with the human condition - so in a very desperate situation that people found themselves in, arriving in that unknown part of the world in the 1700s, starving, diseased and entering the complete unknown on every level, you are really thrown into dramatic, challenging situations. In a lot of ways it has his signature all over it."

When asked about the state of British TV drama, Bremner initially professes ignorance. He hasn't owned a television for so long that the TV licensing folk have stopped sending him letters, and generally prefers to watch films on DVD. He did, however, make an exception for Breaking Bad. "I'm just so crazy about Bryan Cranston in that show, it is a game changer," he says.

Warming to the theme, he continues: "I actually think what is happening in television now is extraordinary. There has never been a time like this, the level of artistic competition going on is fantastic in terms of the standards that people are driving for and expecting from drama. All the great film actors and directors have been brought into the fold and are breaking extraordinary ground.

"It is an international movement, and I think Britain has a way to catch up, but we have always been competitive. The best British directors find new ways to tell stories, whether that is Danny Boyle or Dominic Savage or Mike Leigh. And whenever I tell people who are not from the UK that I am working on a BBC production, they say, 'Oh my God, the BBC are the best!'"

Later this year, Bremner will be back in Scotland and reunited with Robert Carlyle, 18 years after they first shared screen time. If it's not quite the long-rumoured Trainspotting sequel, Porno, that some fans have been waiting almost two decades for, it will be a chance for the old pals to catch up, albeit in unfamiliar roles. Carlyle, as well as playing the title role, will be behind the camera for The Long Midnight of Barney Thomson, with Bremner, Emma Thompson and Ray Winstone taking his direction.

"I'm looking forward to it immensely," says Bremner. "I have not been in that situation before, being directed by someone I have acted with. But it will mean we have that shorthand.

"Robbie directed a lot of theatre before he was even that well known as an actor, and he has also been directing quite a bit in Canada as well. So I'm sure he will be great. If you are around long enough, every job is some kind of reunion - but I have nothing to report on anything else. I await further instructions…"

Although he will be home in time for the independence referendum, Bremner is staying neutral just now - at least in public. Unlike his more outspoken friend Irvine Welsh.

"I haven't talked with Irvine about it yet, but he is a great thinker," says Bremner, carefully avoiding taking sides.

"He is always worth listening to. I am keeping an open mind, but it looks like it is going to get more bloody. There are going to be a lot of arguments and I'm sure the temperature will rise. It is going to be a hot summer.

"Coming back to Edinburgh after you've been in a different environment, you see it with fresh eyes," he continues, clearly looking forward to his return even before he has departed for Australia.

"I love the physical shape of the town, which is built on these old volcanos, so it is very steep. You are always walking up or down a hill. It has great architecture, casting these amazing long shadows and the air is really fresh because you are by the sea.

"The quality of life is pretty decent, you know, it is an easy place to be…"

A Poet In New York will be screened on BBC2 later this month