With the sequel — finally — upon us, the director and star plus author Irvine Welsh, producer Andrew Macdonald and more look back on the 1996 Cool Britannia flagbearer and how it all happened.

The United Kingdom, January 1996. Britpop is in full swing. Oasis' seminal sophomore album What's The Story (Morning Glory), released the previous October, has returned to the top of the U.K. charts and is helping cement the band's status in the U.S. Elsewhere, an all-girl group is preparing to launch its debut single, a song that would introduce the world to the concept of "zigazig-ha." While the current British Prime Minister John Major is commonly regarded as a rather drab, grey-suited politician, a wide-eyed 42-year-old whippersnapper by the name of Tony Blair has 10 Downing Street in his sights. There's a creative, energetic buzz over the land, but the era — which would come to be known as Cool Britannia — doesn't yet have a film that captures the mood.

Enter a low-budget indie from a group of second-time filmmakers and based on the debut novel by a former heroin addict; a movie that would quickly achieve iconic status on both sides of the Atlantic. "Hollywood Come In ... Your Time Is Up" roared the now-legendary posters from (almost) every student bedroom wall, while "shouting lager, lager, lager" bellowed from club speakers, "Born Slippy" becoming the year's first true arms-in-the-air anthem.

Fast forward twenty-one years and the sequel is finally upon us (and has already smashed records in the U.K., debuting to $6.3 million, becoming Boyle's best weekend ever and the third highest 18-rated film opening of all time). As Sony's TriStar Pictures prepares to launch T2 Trainspotting in the U.S. and ahead of its special screening in Berlin, Danny Boyle, Ewan McGregor, Irvine Welsh and Andrew Macdonald sit down with The Hollywood Reporter to discuss the making of the film for which they'll always be known best.

ANDREW MACDONALD (producer) I remember I first read the book on a flight from London to Glasgow in 1993. A friend of mine who's Scottish had given it to me. We were in the middle of post on Shallow Grave and I was going home for Christmas back to my dad's house.

DANNY BOYLE (director) There weren't that many copies around at the time — it was a very cult book. Andrew said, "Have a look at this, what do you think?" We'd made a film and it had turned out pretty good so were obviously thinking about making another. Actually, I'd had a phone call from Sharon Stone while I was in the editing room [on Shallow Grave]. These movie stars are good at looking out for young talent, as it was at the time, and she'd rung me up and said, "I'm doing this movie, do you fancy doing this?" I didn't really know how to behave! But then I started reading this book, and I have I say I still remember reading it, pretty much in one sitting. It was extraordinary. But it was like, what do we do? Because there's not really a plot.

MACDONALD I think the hard bit was convincing John [Hodge, the screenwriter]. It's easy for us to say "adapt that book."

BOYLE That's what's great about John, because his reaction was: I'll just try to write a bit. And he wrote 20 pages and I remember reading them on the tube on the way home. And I knew we were going to make it.

IRVINE WELSH (author) I had been inundated with offers [for Trainspotting] but it was just the matter of finding the right people to do it. I also thought we were past the social realism thing [which many of the offers were]. A lot of the social realism films that came out in the 60s and 70s were about shaming the authorities into providing resources to people in these areas. And we were in a kind of post-Thatcherite world — there was no way you could shame the authorities into doing that anymore. All it would be is making people who weren't in that situation feel good about themselves. It's much more a movie about youth rather than drugs and it was about finding that vitality and optimism — you have everything to play for and you can f— up but it doesn't really matter because you're still young… there's a shot of redemption.

MACDONALD Why I thought the book would be a great film wasn't because of anything to do with drugs. It was because it was a brilliant piece about youth culture and had fantastic characters and humor. I was comparing it to something by John Hughes. I really wanted to make contemporary films about young people, being a young person at the time, and this felt like a brilliant way of doing that. Also, the thing for me and I know for John — it was Scottish. That was a huge thing.

BOYLE I think [Welsh] made a judgment based on meeting us and Shallow Grave. He liked the fact that it was dark and entertaining at the same time, which to be honest we'd stolen from the Coen Brothers' Blood Simple.

Film4 precursor Channel 4 Films, which funded all of Shallow Grave's £1.1 million ($1.4 million) budget, decided to back the project, teaming again with distributor Polygram to put up the entire £1.5 million ($1.9 million).

DAVID AUKIN (then head of Channel 4 Films) Shallow Grave was the breakthrough film. For many years people had avoided going to British films, but it was one of the first British films to recoup its costs at the box office before it even went on TV. So obviously everyone wanted to work with them. They had, as far as I was concerned, carte blanche to do whatever they wanted to do next. And they came up with this idea of Trainspotting. And it seemed great.

MACDONALD We already had a hit film so people wanted to work with us. And we had this relationship with Channel 4 and Polygram, who were doing everything. Working Title wouldn't have made Four Weddings without Channel 4… it was a different time.

AUKIN I know there were lots of people hovering around wanting to take them over. There was one wonderful moment when they came back from seeing some financier who wanted to finance Trainspotting without Channel 4 but wanted them to remove one scene from the film which they thought was a bit gross, which was the toilet scene. So they said no to that and Channel 4 was back in frame.

WELSH But by mistake I sold the rights to the wrong person. I was so f—ing nai?ve. This guy came up to me and said he wanted to make me a huge offer and wanted Danny Boyle to direct. So I assumed he was Danny's producer, signed it over, and Danny comes back to me and is like, "What are you doing?" The next thing was, how the f— do we get these rights back? But the guy was great — he transferred them over. He could have played hardball, but was incredibly saintly about it.

By the time pre-production on the project got underway, Trainspotting had already been adapted for an acclaimed stage production, with Ewen Bremner playing Mark Renton.

EWAN MCGREGOR (Renton) They gave me the script to read and — they always did this — they said: we're not offering it to you, it's just for you to read and see what you think. Obviously once I'd read it, I thought it was the part of a lifetime, and it turned out to be that. I couldn't think about anything else, but they were still being very cagey. I learned later it was because John didn't think I was the right guy for it. Renton is written as a very spotty, ginger guy. We didn't play him quite as ugly as he is in the novel. So what I did was just go and lose tons of weight. When I next went in to see them I was really skinny and at that meeting I said I should cut all my hair off. I literally went out of Andrew's office to a barber and came back with a skinhead. And there was Renton.

MACDONALD In my mind Ewan was always the first choice. We did some casting and that's how we met Jonny (Lee Miller). Gail Stevens the casting director met a lot of Scottish actors. Jonny was the one who wasn't Scottish. Ewen Bremner was in the play — we all knew Ewen. Then came Robert Carlisle. I guess the thing with them was: would they play the part more than were they first choice? We were always worried whether they'd accept it. Bremner was playing Renton in the stage play. Would he do this? Thank god he did. So when the Shallow Grave video came out we made a little trailer from the set that we put at the front, which was Ewan McGregor tied to the train tracks. We had that beautiful thing we're we had a group of people who had just made a film together making another film together with the same financier, same scriptwriter and same leading actor.

WELSH Ewan Bremner was a fantastic Renton on stage, but McGregor brought something different to it, he made that part his own. He just worked so well for cinema.

MCGREGOR I did actually think about trying heroin. At first, early on, I thought: how can you play a heroin addict without having taken it? I was young and I thought, f— it, just do it. And also John Hodge, our writer, was a doctor, so I thought he could probably get us some and administer it so we don't die. I thought I'd do it with Danny. I just wanted to get f—ed up with Danny! But we didn't. Because of course as soon as we started the first thing I remember doing was meeting heroin addicts in Glasgow.

BOYLE It seemed like a natural thing when you're researching a film. But then we met Calton Athletic, this great drug recovery group, and they filled us in with more detail than you could ever discover by doing it yourself. They'd been to hell and back many many times and they were a huge help to us. I remember taking Ewan to one of their meetings. They also gave practical advice on set — we brought them with us. They were brilliant. [Members of Calton Athletic actually appear in T2 dancing with their shirts off in the Loyalist pub]

MCGREGOR As soon as I met the real deal, I thought it would be hugely disrespectful to them to be taking heroin.

Shooting began in June 1995 and went on for 35 days, most spent in an abandoned cigarette factory in Glasgow (despite the Edinburgh setting). It was there where the iconic Worst Toilet In Scotland, dead baby and cold turkey scenes were shot.

WELSH On the set, you could feel the energy, everyone was walking around with a big smile on their face. You could tell something special was happening, there was something crackling in the air.

MACDONALD I had that concern [about the more extreme scenes] all the time. That's why we were very keen to make the film cheaply. Because we knew that there was a responsibility that telling this story might not translate to box office and commercial success. We felt very responsible about that, but we also knew we had to do it. So that's why it's just seven weeks and under two million quid. I remember going into the cutting room with Keith Allen, who had been in Shallow Grave and had a little part in this, and he introduced us to [Blur lead singer] Damon Albarn, and both of them watching the opening sequence and being absolutely shocked. This is a rock 'n' roll guy and a bad boy actor. And they said: this will never get released.

The editing took place in London over eight weeks by regular Boyle collaborator Masahiro Hirakubo, After the sound — and, crucially, the soundtrack — was nailed, Trainspotting had its world premiere in Scotland, simultaneously screened in Glasgow (in aid of Calton Athletic) and Edinburgh. The film was then released across the U.K. on Feb 23 and met with widespread acclaim, going on to earn more than $18 million at the local box office and becoming an instant foundation in the Cool Britannia and Britpop explosion.

MCGREGOR I sort of arrogantly always assumed it'd go the way it went. I was 23 years old and I believed in it, I really did. The book swept the country over here — everyone was reading Trainspotting. As we were making it I had no doubt that it was going to be amazing. I don't think any of us could imagine it'd become what it did. But the same time I'm not totally surprised. I remember feeling that time in the mid '90s after it came out and took off, feeling like a bit like shit, feeling like someone in a band.

WELSH I didn't really expect it to happen. It was a time when everything was going global — the internet was about to take off big time, the whole British culture, and Britpop thing was being sold up for export, and it was one of the big standard bearers of that charge. It was something that I didn't really anticipate would be as big as it was and something that still surprises me now.

Trainspotting then went to Cannes for a special midnight screening, followed by a celebrity-soaked afterparty that quickly became part of festival folklore (Welsh was rumored to have been found by the Hotel Du Cap swimming pool with Noel Gallagher at 7am the next morning).

AUKIN We did actually submit it for competition. But I think they were a little bit frightened of it.

BOYLE I remember the Cannes party. It was super glamorous but I was f—ing livid because some of the Calton Athletic guys couldn't get into it. They'd hitchhiked down to France and they wouldn't let them into the party. Elton John and Mick Jagger were there, but these people whose lives this was about can't get it. Anyway, we got them in eventually!

Before Trainspotting could be released in the U.S. (Miramax picked up the rights towards the end of shooting), a few edits had to be made to ensure it recieved the R rating.

MCGREGOR I don't think you see my penis in the American version. When I come out into the corridor and snap the Durex off, I think you can see my penis in the British one, but not the American one.

MACDONALD The condom had to come out. They didn't like that. And, if I remember, the prick of needle going in. To get the R rating they insisted. I think they had this thing that you couldn't see a needle break the skin because that would lead to more misuse of opiates.

Due to the rather thick Scottish accents, the opening scenes of Trainspotting were also dubbed for American ears before its U.S. release.

MACDONALD There's a lot of mystery about [the dubbed version]. Danny and I don't remember it happening. The actors when we made T2 were all telling us that they did it, but nobody seems to have heard it.

MCGREGOR I've heard it. We were forced to rerecord the beginning, the first 15-20 minutes. So if you listen to the American version of Begbie's story of when he throws his glass over his shoulder you can actually understand some of the words, which is not the case in the original. I was disappointed. I downloaded it to watch on my way to shoot the sequel and as soon as it started, I was like, "Oh f—, it's the American one."

The film also stirred up sizable controversy, most notably from Bob Dole during his 1996 presidential campaign when he says the film "glorified heroin," only to later admit to not having seen it.

WELSH It was great for us. There's two things you want whether you do a film or a book. You want the approval of cool people and the condemnation of an asshole. The condemnation of a prominent asshole is absolutely fantastic.

MACDONALD I remember being on [BBC current affairs show] Newsnight arguing with a nun. The nun was saying it was depraved, and naturally she was the only person in the studio who hadn't seen the film. John Hodge always says that on [BBC radio's daily faith-based reflection] Thought for the Day, on the day that it opened, somebody was offering condolences for those who were about to see it.

AUKIN Channel 4 were thrilled. Controversy and Channel 4 are handmaidens, they loved it, they relished it. The only thing that would have upset them was to have gone unnoticed. That would have made them really pissy.

Trainspotting was finally released in the U.S. on July 19 on eight screens (its per screen average of $33,000 is more than four times higher than the top film, Independence Day), going on to earn $16 million. Six years later in 2002, Welsh released the follow-up book Porno, which would — eventually — lay the foundations for T2.

WELSH I had all sorts of offers for the rights, but I kind of made a gentleman's agreement with Danny, Andrew and John and said, "Look, I'll hold off until you guys are ready, if you ever are." It could only really be done by those guys. I wouldn't want to do it with anybody else.