Phil Collen remembers how he was secretly auditioned for Def Leppard during the making of Pyromania without knowing it

Def Leppard are certainly not slacking off; May sees a new album with Drastic Symphonies 'deconstructing' hits and deeper cuts at Abbey Road with the Royal Philharmonic Orchestra, they're heading out with Mötley Crüe in the UK and mainland Europe and there's a retrospective book. The latter is Definitely: The Official Story Of Def Leppard and it's a real treat for fans.

Told in their own words, it's full of insights from members present and past – including archival insight from late guitarist Steve Clark – it's also packed with classic photos from the Leppard vault. And there are some great memories shared – including the interesting way Phil Collen was recruited to replace Pete Willis after the original guitarist with the Sheffield band was fired during the making of 1983's Pyromania. An album that would see the Brits conquer the US. But Phil didn't even know he was auditioning to join Def Leppard at the time. 

"I honestly thought, 'Yeah, this stuff sounds amazing'" Phil recalls with us about the time he was called into the studio by his friend and Leppard singer Joe Elliot to help out with some solos for the sessions with producer Mutt Lange. "They'd done all the backing tracks, the vocals and it was genius. Then Mutt said, 'What would you do over that?'"

'That' ended up being the song Stagefright and Phil aced the solo.

"When Phil came in to play on Stagefright, we didn't hover in the control room looking through the glass," recalls Joe Elliot in the book. "No one needs that kind of pressure. We took ourselves off to the kitchen area and drank tea. After about 15 minutes, Mutt came rushing out and said, 'You gotta come and hear this,' and he played us Phil's solo. We felt like we'd found our Eddie Van Halen."

"For me it was like, wow, this is heaven, you know?" Phil remembers with us about being asked to join the band and contribute to the rest of the album. "And then we went on tour and here we are 41 years later."

It's too easily forgotten that Leppard were the first rock band since Deep Purple and Led Zeppelin in the 1970s to hit big in America, and Phil credits the song Photograph as the breakthrough moment. Not bad for four Sheffield lads and their new Leytonstone-born guitarist.

"I mean, it was a hybrid – it was a rock hybrid," Phil tells us. "It was so melodic but the backing vocals and the vibe of it was still a rock band, it was still a British rock band. There is a difference – I remember hearing like Journey, Styx, REO [Speedwagon], and their vocals are wonderful, but they were very sweet and sounded very American. But there's another part to British music and it's the Sex Pistols and it's like that [adopts Johnny Rotten voice], 'No future!' It's just got this kind of vibe that that we still had [as] part of our vibe, if you like, even going into America. 

"So we retained some of the British, I don't wanna say punk ethos, because it's not really that, but it was it there was a hard rock thing that was definitely British, and it was retained. And Mutt Lange – genius, he was able to, to make this hybrid work. And it's got these beautiful melodies with a rock band, an AC/DC-style rock band, doing all this stuff, with a bit of Queen in there, but unmistakably Def Leppard. 

"And then when I played that solo, it was a bit of a shred solo but it was very melodic, and I double-tracked it, so [I] couldn't go too far off the path with it. Also, MTV was exploding as well and we didn't look like other rock bands. It was like Duran Duran-ish, almost because we were really young. And it had all these elements at the same time. So that song and that video definitely did the trick."

• Definitely: The Official Story Of Def Leppard is published by Genesis Publications and released on 18 May. Find out more at Genesis Publications about special editions and preorder the hardcover standard edition at Amazon.