The best-selling Edinburgh author said 14 tracks have been created with songwriting partner Steve McGuinness for the planned production, which is being lined up for London’s West End.
The writer, whose first TV show Crime is due to be launched this week, revealed that he is working with Phil McIntyre, one of Britain’s leading entertainment producers, on the musical.
His previous West End shows have included hip-hop musical, Into The Hoods, the stage adaptation of Roddy Doyle’s novel The Commitments and the hit musical based on the classic sitcom Only Fools and Horses. McIntyre has also worked with Sir Billy Connolly, Steve Coogan, Rowan Atkinson, Ricky Gervais and Peter Kay.
Welsh’s 1993 novel was adapted for the stage within nine months of its publication.
Harry Gibson’s production for the Citizens Theatre in Glasgow, originally starred Ewen Bremner in the lead role of Renton. After being overlooked for the part in Danny Boyle’s film in favour of Ewan McGregor, Bremner took on the role of Spud.
A new version of Gibson’s production, described as “immersive 90s rave theatre,” was launched in 2017 at the Edinburgh Festival Fringe, where it was performed in a tunnel beneath the EICC.
Welsh said: “I don’t want to jinx something that’s in development, but my songwriting partner Steve and I have done 14 brand new songs for a Trainspotting musical.
"We do a kind of techno act together, but we’ve stepped up to write urban house, blues, jazz, disco and rock ‘n’ roll songs and power ballads.
"We’ve got the songs and we’ve got a script for it. We’re looking at things like casting, choreographers and set designers.
"We’re looking at doing it about a year from now at the earliest, but I think we’ll probably try to go straight into the West End. That’s the ambition for it.”
Welsh also revealed that fellow Edinburgh author Jenni Fagan is working on the adaptation of his novel The Blade artist into a TV series, which will see Robert Carlyle reprise Begbie, his terrifying Trainspotting role.
He said: “We’ve had masses of people expressing an interest in it. We want to take the heat off it for a bit now and just get working on developing the scripts.
"Jenni is such a brilliant writer and will do a fabulous job. I didn’t want do to it myself because it’s too recent a book for me. I want to be excited by it again.”I think Jenni will give it something else and another twist that will make it more interesting.”
Crime, which has been adapted from a 2008 Welsh novel of the same name, features Dougray Scott in the lead role as Ray Lennox, a trouble detective battling addiction demons and past traumas as he hunts for a killer.
Welsh, who has written Crime with regular screenwriting collaborator Dean Cavanagh, said the characters in the six-part show had been deliberately “written up” so they could feature in possible future series of Crime.
He added: “I’ve got so into this that I’ve actually written another Ray Lennox book, which will be coming out in August.
"I would love to have a shot with Dean to work with the characters again and give them another series.”