Matt Willis is gearing up for what he describes as the most important week of his life: on Monday his debut single, Up All Night, is in the shops. He calls it “stadium pop” — a sound he hit on after a boozy night out soundtracked by Van Halen’s Jump.

“I never wanted to go solo,” he announces, perched in the window of his favourite Muswell Hill café. “It sounded really f****** boring!” Listening to Willis’s album, “stadium pop” seems to mean helicopter sound effects, glockenspiel solos, stupendous key changes and the unified handclaps of 100,000 pop fans underpinned by a pile-driving, freshly produced rock sound. Not very “f****** boring” at all, then, but you can see why Willis may have been concerned about going it alone, because as the bassist in Busted he experienced the excitement of accidentally changing the face of 21st-century British pop. The instrument-playing, songwriting trio — three wildly eccentric and excitable friends — raised the expectations of a generation of teenage pop fans, effectively killing off the notion of the conventional, Take That-style boyband.

In the past decade countless former band members have discovered that none of the above equates to instant solo success, and things could have been even riskier for Willis. After all, he was not the much-talked-about songwriting talent in Busted — that was James Bourne, the self-confessed nerd and principal driving force behind the band’s numerous No 1 singles and two multiplatinum albums. Nor was Willis Busted’s credible and almost supernaturally good-looking member — that was Charlie Simpson, whose decision to concentrate on his noisy side-project Fightstar effectively ended Busted’s short chart career at the beginning of 2005. “I felt like the comic relief,” Willis admits. “So I’d play up to that in interviews. I knew my place in the band — I accepted what I was.”

Except that’s not precisely what Willis was. Having shadowed Busted on countless TV, radio and press interviews during their career, it was clear to me that when Simpson was in a huff or absent, or when Bourne was embarking on wide-eyed monologues about long-forgotten American high-school flicks, Willis would turn on the charm, making an effort with fans, label weirdos and hangers-on. What became apparent — unusually so — from watching these encounters was that Willis, brought up by his mum in a working-class home on the less leafy side of Molesey, Surrey, wasn’t faking any of it.

Certainly the real nature of Willis’s personality — loyal and generous towards his family and friends, terrified of letting anybody down, driven by a desire to make sense of his life and his talents — was done a huge disservice by the efforts of the showbiz columnist Victoria Newton. Having titled Willis “Beer Matt”, Newton must have been cock-a-hoop when he checked in to the Priory in the wake of the Busted split.

“Going into rehab was a bit of an over-reaction,” Willis admits, but he did learn two things from his time at The Priory. First, he says, “the problem wasn’t that I couldn’t control myself — it’s that I didn’t want to”. Since getting his new music in check, that concern has now passed. The second, more fundamental lesson, was this: “Basically, I just needed to stop getting p***ed all the time.”

Unfortunately, as you might expect from a man benefiting from three years’ worth of interview training, Willis found it difficult to respond to their line of questioning. “They'd tell me something about myself, and I’d say: ‘Well, that’s not actually what I’m like.’ They’d say: ‘You’re in denial.’

Willis found out about Busted’s demise by accident when, on the penultimate night of the band’s second arena tour, he bumped into Simpson’s parents in the foyer of his manager's hotel. Smelling a rat, he called his manager and was told that Simpson was “99 per cent leaving the band”. In the end, Bourne found out the news from his dad, who had also found out by accident. “He wanted a decision on whether I was staying in Busted. It would have been s*** without Charlie, and I said we had to call a press conference.”

That was in January last year. What followed was the inevitable soul searching, then drinking, then recovering, before serious plans for a return could even be entertained. Fortunately, things began to fit into place organically. Members of the un-Googleable rock outfit A, who, unbeknown to Willis, had approached the Busted team years ago to express an interest in establishing a songwriting partnership, came on board to work on new material, which forms the majority of Willis’s debut album, conjuring this signature “stadium pop” sound. It’s a sparky, likeable and sometimes witty mix of modern pop and rock. Robbie Williams is an inevitable reference point — but if you throw in Green Day and Def Leppard you’ll be nearer the mark. Refeshingly, Willis is also free of muso hang-ups — the sort of perky, likeable persona the crumbling pop industry desperately needs.

“I want to be ridiculous and slightly cool,” Willis concludes. He pauses. This would traditionally be the point when a musician would backtrack and say he just wants to do what he does and if anyone likes it that’s a bonus. Willis’s mind is already elsewhere. “I want my third video to have a talking horse in it.”

Up All night is released on Monday by Mercury