Irish punk singer Gavin Friday, the man sometimes called Bono's muse, was this week credited with rescuing U2's first big American number one - by identifying what it was missing!

According to guitarist The Edge, the band were struggling to complete their signature hit 'With Or Without You' and had even considered abandoning the 1987 track altogether before Bono's childhood friend arrived in the studio.

'We were making The Joshua Tree album and were having trouble with one of the songs,' The Edge told RTE documentary Ladies and Gentlemen, Gavin Friday - a documentary on the underrated Irish punk singer. 'It just wasn't coming together. I'd just received a new guitar, the Infinite Guitar, so I was in the room playing with the guitar, oblivious to the fact that the others were in the other room listening to a raw blend of 'With Or Without You.'

'I think they just had the bass and the drums up. Gavin and Bono could hear this guitar and Gavin said, 'What’s that? That’s it!' With the addition of the understated guitar part, the song was chosen to be the album's lead single and went on to top the Billboard Hot 100 for three weeks and reached number four in the UK charts.

In an interview for the Arts Lives documentary, Friday said of his relationship with U2: 'I'm a cross between their mother, their father, their schoolteacher, their midwife, their communicator.'