Cyndi Lauper on how Kinky Boots stepped up to be a stage hit

The story of a struggling Northampton shoe factory perhaps isn't the most obvious idea for a hit stage show, but Kinky Boots has just celebrated five years on Broadway, is into its fourth year in the West End and is now going on a UK tour.

The stage musical, adapted from a 2005 film, which in turn was inspired by a true story, puts the spotlight on a man who saves his factory from collapse by producing erotic footwear inspired by an encounter with cross-dressing cabaret singer called Lola.

The show was a good fit with audiences and critics, and won six Tony Awards on Broadway and three Olivier Awards in the West End.

Cyndi Lauper, who wrote the music, still can't quite believe it.

"I remember first seeing it in Chicago and watching the audience and they were up, and I kept saying to the producer, 'Is it a hit?' and he'd go 'I dunno, Cyn'," the singer tells BBC News.

"Even when it won best musical [at the Tony Awards], then I said 'OK, is it a hit now?' and he was like, 'OK yeah, it's a hit'."

Cyndi Lauper has gone from solo pop star to musical composer

The musical's 12-month UK tour will begin, fittingly, in its spiritual home of Northampton in September.

The show explores themes such as friendship and self-acceptance - interspersed with some hummable tunes.

"I just think it's an important message to get out, and it makes so many people so happy," says Cyndi.

"In this day and age, it's good to stress acceptance, and changing the world when you change your mind."

So how many times does Cyndi estimate she's seen the show now?

"I have no idea, because I've been watching it since the beginning in Chicago. I do come back again and again because I check the sound," she laughs.

"It's so different in every territory, and that's what makes it interesting. It's everyone's take on it.

"In Germany it's different. In England it's important because the story is from England. I actually grew up next to two factories, so I really related to this story."

David Hunter, plays Charlie in the London production, opposite Verity Rushworth as Lauren

Writing the book for a musical was a very different creative process to performing as a solo artist in the 1980s - but, Cyndi says, it was one she found fulfilling, mainly because it involved working with a team.

"Well, it was different in the '80s for me," she explains.

"I was very focused on taking care of my voice, I had to do this, I had to do that, the visual... there were days when I worked 24 hours. And I'd be like 'wait a minute, I didn't go to sleep today, I have to go to sleep'.

"It's different... this is a collective, and it's the biggest band you'll ever have. Even when the actors come in you're changing things because you want it to sound like it's from them. It's like wearing a dress, not everybody's the same size, so you gotta tailor it. So that's what we were doing."

She adds: "You work hard on something together with your team. It was a big team, you know, and I'm just like the famous guy here. I represent.

"You don't know if it's gonna... you just lose track of standing back and watching people watch it. And when you see how happy they get - it's amazing."

As the show enters its fourth year in London, Cyndi says she'd "like to see it do at least five years, maybe six".

"[Long enough] for people to just come and think of it as having a good time, and feeling the love. Because there's a lot of different kinds of people in the show, not everybody's the same.

"And it's about friendship. Not just acceptance and accepting yourself, but friendship and family, and saving people's jobs, because you grew up with them."