London - Trainspotting 2 will begin filming in May.
Ewan McGregor has confirmed that work on the long awaited sequel is set to begin shortly and claims the script is "really, really, really good".
He said: "We haven't started yet, we start shooting at the end of May. The script only arrived very recently, which was really, really, really good.
"I think, if that had not happened, none of us would be into it. I think we're all sort of somewhat protective of what Trainspotting means to people, and what it means to us."
The 44-year-old actor - who is reprising his role as Mark Renton - also insisted he wouldn't have signed up for the sequel if it hadn't had an "extraordinary script".
He added to Collider.com: "None of us want to make a poor sequel to it. So had we not been presented with the most extraordinary script, which we were, I think we wouldn't be making the sequel. But because we were, we are."
Meanwhile, Robert Carlyle - who has also signed up for the sequel - previously admitted he is "wary" of the new movie.
He said: "It's nerve-wracking to a certain extent, because I'm obviously aware of just how much people loved the original film.
"People still quote lines to me on a fucking daily basis. I get it everywhere; I can't fucking escape it! But I'm grateful for it too - Begbie has been fucking terrific for me and my career.
"So therefore - and I think probably if you asked the rest of the boys, they'd feel the same - I'm slightly wary about it all."
Director Danny Boyle hinted in 2013 that the Trainspotting sequel would explore what happened to the characters. The original film, which is based on Irvine Welsh's novel of the same name, followed the lives of a lost generation of heroin addicts in Edinburgh, Scotland.
Boyle previously revealed that the sequel would possibly be "loosely" based on Welsh's follow-up novel, Porno.