He's played the morally dubious Billy Flynn in Chicago, the devilishly delicious Daryl van Horne in the Witches of Eastwick and now he's splitting himself in two to play Dr Jekyll and Mr Hyde. STACIA BRIGGS enjoys a double dose of Marti Pellow ahead of appearance at Norwich Theatre Royal.

'I've learned the correct way to kill someone cleanly by snapping their neck. I know how to bludgeon you to death too, but the neck snapping requires less effort.'

Marti Pellow, former frontman of Wet Wet Wet and now the leading man in a new production of Jekyll and Hyde: The Musical, delivers this information with a trademark smile. It's definitely Dr Jekyll who has turned up for this interview.

'The stunt arranger had worked on Bond movies and he knows the best way to kill someone. And it's important to be able to kill someone smoothly when you're Mr Hyde: he's a man who kills with real panache.'

Marti is currently starring as the brilliant but obsessive scientist whose sadistic alter ego wreaks havoc across Victorian London in a dark tale of love, redemption and the seductive power of evil.

'It's great, because I get to play two parts and they're both leads!' laughs Marti, reclining in a chair in one of the Royal Institute of Great Britain's book-lined libraries in central London.

'You might think that it would be harder to bring Hyde to the stage, but actually the most challenging role is Jekyll. I know Hyde will take care of himself with the ammunition he has within the score and the character.

'Jekyll, though, is a very different character and the difficulty lies in trying to make the audience want to be part of his journey. People love Hyde – baddies get all the best lines.'

Marti first read Robert Louis Stevenson's dark tale of duality when he was a pupil at Clydebank High School where he met the friends who would later join him in Wet Wet Wet to become one of the most successful bands in British pop history.

'It is a very dark story,' he says. 'For a start, 90% of it is set at night…

'I wanted my performance to be quite subtle – there's more power in a whisper than a scream, and I didn't want to be on stage, drink my potion and suddenly turn round with a pair of fake bushy eyebrows stuck on and say 'ta-da!'.'

I first met Marti Pellow in 2008 at the theatrical launch of The Witches of Eastwick at Norwich Theatre Royal.

Charming, passionate and funny, I'd deposited the experience in my memory bank as one of the rare occasions that I'd met a celebrity who wasn't disappointingly one-dimensional, dull or downright rude.

Endearingly, Marti remembers the interview too and makes a special point of thanking me for the piece I wrote (which I must boastingly point out was hailed as 'the best ever' by his official fan club – probably because I asked Marti if he was 'hairy all over') and giving me not one, but two kisses.

'I love Norwich,' he tells me.

'I've got some great memories of Norwich from when I was there with Witches and it is a beautiful, beautiful place. Incredible architecture and good audiences and I'm really looking forward to coming back.'

Marti was approached to star in Jekyll and Hyde: The Musical by legendary Oscar-winning composer Leslie Bricusse, who has also penned such classics as Goldfinger, You Only Live Twice and the soundtracks of hit movies including Doctor Dolittle, Scrooge and Willy Wonka and The Chocolate Factory.

Having heard Marti's version of one of his songs, Who Can I Turn To? Bricusse telephoned to offer his congratulations and to suggest that he'd be perfect to star in the musical he'd written the lyrics for, Jekyll and Hyde.

Marti didn't need to be asked twice: the chance to follow in the footsteps of Sammy Davis Jr, Frank Sinatra, Barbra Streisand and Shirley Bassey was irresistible.

'I flew to New York to meet Leslie and his co-writer, Frank Wildhorn, and I pitched them my ideas for the score. I wanted to bring something to the table and they were keen that the musical should finally be as successful in the UK as it has been in the States,' says Marti.

'Vocally, the piece is a huge challenge. As they say, it's 'a big sing'. The songs and the script have been reworked for me and in an acting sense, it's a far bigger role than either Chicago or The Witches of Eastwick.

'I've had to really work on the tonality in my voice. When you do a piece like this, your bag of tools has to change. I went to my bag of tools and suddenly thought 'I haven't got that!' and it made me really explore what my voice could do.

'I also have to think about the differences in Jekyll and Hyde's voices: the spoken voice of Dr Jekyll is very soft and polite whereas Hyde is more sensual and carnal with all this contained anger. Sensual and psychopathic!'

'For me, it was important that Hyde was accessible, that people care for his plight, because within the space of a song he's out on the streets of London, killing. To find the part of Hyde that people sense in themselves: that's what I want to do.'

Marti has worked with the vocal coach who prepared Jude Law for Hamlet and, like Dr Jekyll himself, is a man possessed by a passionate work ethic.

'To a lot of people in the theatre, I'm still 'that bloke from Wet Wet Wet' who fancies himself as a bit of an actor. I'll always be 'that bloke from Wet Wet Wet', but what I do is I really invest in the work,' he says.

'I'm the first there for rehearsal. I learn all my lines. I do my research. I'm the last out of the door at night. I dig in: it's down to the working-class ethic installed in me by my parents, I think.

'I grew up in a council house in Clydebank watching movies and seeing how all the great actors showed the different emotions. I learned from the greats, you could say!'

Now entrenched in musical theatre with some impressively meaty roles on his CV, it seems hard to believe that Marti once believed that all it involved was 'some people on stage singing about nothing'.

'I've fallen in love with the theatre and it surprises me more than anyone else,' he says.

'I love the feeling you get from the audience, the relationship that you have with them. I love the camaraderie of being on tour and the discipline of performing every day.'

In fact Marti is so enamoured with musicals that he's even started to write one himself with the working title Scarlet. Based in 1920s Soho, it is the story of a tailoring firm which switches on the red light in the evening to become a knocking shop.

'I suppose if you write it, you can make sure you give yourself a really great part!' he laughs.

Having recently celebrated 12 years of sobriety, Marti's own Mr Hyde is currently, well, in hyde-ing, but he still embraces a somewhat dual personality.

'I'm an entertainer. Marti Pellow is a jacket that I put on and as long as I know when to take it off, that's OK. I sing songs, but away from that I have a family and my life isn't all about what happens up there on the stage,' he says.

'I consider myself very lucky that musical theatre is something that's come to me late in my career. It's a testament to my fan base that they have afforded me the luxury to do something that I love so much.'

Having committed the next six months to the show, Marti continues to enjoy recording albums and looking forward to future musical productions – for a start, he'd love to get his teeth into another of Leslie Bricusse's creations, Scrooge.

'I love the whole Dickensian, Victorian feel – British theatre does it so well,' he says.

'At the moment, though, I've got my hands full with Jekyll and Hyde. I'm just glad that it's my leading ladies that have to wear the corsets and not me!'

n Jekyll & Hyde is at Norwich Theatre Royal from June 6-11, �30.50-�6.50, 01603 630000, www.theatreroyalnorwich.co.uk

www.jekyllandhydethemusical.com

MARTI PELLOW: FACT FILE

n Marti Pellow's real name is Mark McLachlan.

n He formed a band with three classmates from Clydebank High School aged 17.

n The band was called Vortex Motion and then changed to Wet Wet Wet, a title taken from a Scritti Politti song.

n Signed to PolyGram in 1985, the band scored their first hit two years later with their debut single, Wishing I Was Lucky which reached number six in the charts.

n The band's first number one was a cover version of the Beatles' With a Little Help From My Friends, recorded for

the charity ChildLine.

n In 1992, Goodnight Girl became Wet Wet Wet's first self-penned number one. Two years later, Love Is All Around, a cover of the Troggs' single was a huge international hit, spending 15 weeks on top of the British charts.

n Before it could equal the record for the longest-standing number one single (held by Bryan Adams), Pellow insisted on its deletion because he was bored with its chart domination.

n In 1999, Pellow quit Wet Wet Wet and went into rehab to fight a debilitating heroin addiction which had caused him to collapse in public.

n He returned to the public eye in 2001 with his debut solo album, Smile, and went on to play Billy Flynn in the musical Chicago in London's West End.

n Wet Wet Wet reformed in 2004 and continue to work together.

n Pellow is in a long-term relationship with his fianc�e, former Miss Scotland Eileen Catterson.

n He was placed sixth in a 2003 Glasgow Herald poll to determine The Most Scottish Person in the World (Jimmie Krankie won).

n Jekyll and Hyde: The Musical features the hit song This Is The Moment and ran for more than 1,500 performances between 1997 and 2001.