THE old adage that there are two sides to every story has never been as true as at the Theatre Royal in Plymouth next week, when Marti Pellow, the singer, songwriter and front man of Wet Wet Wet, appears in the touring production of the hit Broadway musical, Jekyll & Hyde.

Although Wet Wet Wet are one of the most successful British bands of all time – their 1994 single Love Is All Around, featured on the soundtrack to Four Weddings and a Funeral, continues to be one of the top five highest selling singles and most played songs of all time in the UK – Marti has been busy forging an alternative stage career in the West End, on Broadway and on national tours with the musicals Chicago and The Witches of Eastwick.

"I think that musical theatre came to me in my mid-30s really," he says. "It was just by chance singing with Ruthie Henshall in 2002 for the Teenage Cancer Trust that was seen by the producers of Chicago. And Pete Townshend had tried to convince me to do Tommy years ago. I never really foresaw it happening though and it's been a pleasant surprise. To do something that is relatively new to me means I'm a bit like a kid in a candy store."

The years of touring with Wet Wet Wet have, he believes, stood him in good stead for the rigours of a musical.

"I've been singing for hours and hours for 30 years and I've done places from Madison Square Gardens to Milton Keynes.

"I think being a singer-songwriter means that you are in the habit of being a storyteller anyway – there is a metre to the writing, and I think how you colour it and engage with your imagination is how it makes musical theatre. I try to keep it as simple as that and it seems to work," he says.

Even though Jekyll & Hyde is nearing the end of its tour, Marti is still hugely excited about it. "It's been great. When I pick the projects I want to get involved in, it's important to me that it isn't Groundhog Day every day.

"With this, I am always trying to keep polishing my performance and approaching it in a different manner within the parameters I have.

"It's a challenge and, of course, I'm still learning from it, even though we're approaching the end of the tour. I think the beauty of it is that when you're doing eight shows a week you have got to have a lot of passion for the project you do," he says.

The main challenge in Jekyll & Hyde is having to play two very different characters – one a brilliant but obsessive scientist, and the other his sadistic alter ego who wreaks havoc across Victorian London.

"I think being able to do it successfully – that is the gift of your imagination. When you start on that flight with Jekyll and Hyde you feel at the beginning of the show that you must want to go on it with Doctor Jekyll, but then you find that you care for both characters. Here lies the dichotomy of the two and the challenge – even when you're splitting between them – is that you get seduced by the passion of Edward Hyde," he says with a smile.

When the tour finishes at the end of the month, Marti is preparing to reimmerse himself in his own music for a while.

"I think I will continue to do my singing and songwriting," he says. "I've been working on a new album with music from my own country. It is a genre I've always wanted to explore, so I think I might make an album of Celtic music."

Jekyll & Hyde at the Theatre Royal in Plymouth runs from Monday to Saturday, 23 July. For more information or to book tickets telephone 01752 267222 or see www.theatreroyal.com.