Nail, who enjoyed Tv and chart success in Europe with hit show Auf Wiedersehen, Pet and songs including Love Don't Live Here Anymore, had turned his back on showbusiness after realising he didn't need to work anymore.
He was living a quiet life in Chelsea, London when his old pal Sting tracked him down in 2010, and Nail immediately agreed to help.
He says, "I was quite happy to do nothing and be anonymous... Sting asked me if I would helped him put some guide vocals on some songs that he was amassing for this project... I said yes and I meant no.
"I thought, 'When the time comes, I'll pull a sickie (fall sick)...' but slowly, as the songs materialised, I realised that, for me, it was an important journey that I was gonna go on, and that's how I got dragged out of retirement."
Sting, who appeared on a recent Inside the Actors Studio Tv special with Nail, confessed he modelled the shipyard foreman he created for his musical on Nail: "I had designs on Jimmy from the very beginning of this."
Ironically, Nail's father was a foreman in a Newcastle, England shipyard, and he admits the show means an awful lot to him: "I stand in the wings just before I walk on and I can't describe the pride that I feel because I feel like I'm about to tell people about who we are, why we are who we are, what we are... I'm so bursting with pride I can't wait to get on there and get started."
The musical opens at Broadway's Neil Simon Theatre on Sunday (26Oct14) following a string of previews.