Sweeney Todd the Demon Barber, the big-hearted (and big everything else) Edna Turnblad in Hairspray, and now Mack Sennett in the touring production of Mack and Mabel – you could say that Michael Ball has a really good nose for juicy roles in crowd-pleasing musicals.

It so happens, he also has a highly selective nose for how these characters smell on-stage – to the point that he assigns each one a signature perfume or cologne. “Mack is Eau Sauvage by Christian Dior,” says Ball and he promptly laughs uproariously, remembering how he went round all the perfume departments doing sniff tests until he found one whiff that conjured up Mack’s heady days of movie-making in what was to become Hollywood. Ball then reveals that “Sweeney was Bay Rum from Geo F. Trumper – very traditional – while Edna was Madame Rochas, and that was really because my Gran and my Mum wore it and it reminded me of them.” He now chuckles to himself, perhaps at a private family joke – but doesn’t further embellish the connection with Edna!

Instead, he admits that getting a character’s on-stage smell right is – like the little ritual of face-tapping before curtain-up, or the need to do all the dressing-room stuff in the same order, always – all part of a raft of superstitions he totes round every venue or show he plays in.

“I drive people mad with it – I know I do. That very old thing of not whistling back-stage – if you’re in a musical, everyone tends to whistle without even noticing. I notice – and then they have to do the whole going outside, turning round three times, spitting rigmarole. No real flowers on-stage, that’s another one – bit of a tie-up there, with Mack’s ‘I won’t send roses...’ number!”

He is, of course, joking about something he takes very seriously indeed: making sure an audience is given a truly great night out. “None of us knows exactly what it is that makes a show work,” he says. “So that’s where the superstitions creep in. When it all clicks on-stage, you want it to be like that every night, so you try to recreate every single detail...” There’s a pause, a semi-shrug and a smile. The magic secret, as he’ll tell you more than once is down to hard work. And as he starts to explain why talent has to go hand-in-hand with hard graft and a willingness to learn, Mack Sennett slips into the room and stands at Michael Ball’s shoulder.

Given that Ball was the initial driving force behind this new production of Mack and Mabel, it would be mighty strange if he wasn’t enthusiastic – effusive, even – about the show. His wonderfully articulate lava-flow of words, however, is as much a fan-letter to the late Mack Sennett as an interview promo for a musical that has had more downs than ups since it opened on Broadway in 1974. He’ll readily tell you about Mack the lad – how, born in 1880, “he grew up on a dirt farm in Canada, doing the same chores every day. To help him get through it, he’d make up crazy stories in his head – just like the movies. Only the movies didn’t exist in those days. He’d play these scenes out to his friends on a Sunday after church, and the greatest sound he said he ever heard was when they started laughing for the first time. And I can so relate to that. That laughter from an audience? There’s no better sound. It’s intoxicating... it’s inspiring... it’s your motivation to go out and do more, get better, take risks, never rest on your laurels.”

His own first sip of entertainment success came with his West End debut as Marius in Les Miserables in 1985. Ball had in fact trained as an actor but, in pursuit of an Equity card, had auditioned for the first thing that came along: Godspell. “I can still feel that moment.” he says. “Walking on stage, singing 'Prepare Ye, The Way of the Lord!' and realising in an instant that it was the most marvellous thing that had ever happened to me. Experiencing how music can connect you to – and also convey – real feelings. And take an audience on a journey more powerfully than anything else. I fell in love with musicals on the spot.”

Some 30 years later, Ball is arguably the biggest name in British musical theatre, with a string of high-profile leading roles to his credit, not one but two Olivier Awards for Best Actor in a Musical, a successful recording and broadcasting career and – as of June this year – an OBE. Unlike the ill-fated romance between Mack (Sennett) and Mabel (Normand), Ball’s love affair with musicals seems to be going from strength to strength, so much so that he’s joined collaborative forces with Chichester Festival Theatre to stage Sweeney Todd (2011) and now Mack and Mabel which comes to Edinburgh next week.

“When I was doing Sweeney with Chichester, they asked me if there was anything else I’d like to do,” says Ball, “and that was my chance! I said Mack and Mabel because I think it’s got everything you want in a musical. It’s got glamour, it’s got comedy, it’s got amazing musical numbers and it’s got a true romance set against the backdrop of the silent movies in Hollywood.”

Ball will give you a forensic breakdown of Mack and Mabel’s qualities, from the glories of Jerry Herman’s music and lyrics to the compelling sweep of Michael Stewart’s book – and he won’t flinch from the well-documented fact that despite its provenance, Mack and Mabel is tagged with a very on/off history.

“If you’re going to tell the truth about Mack Sennett and Mabel Normand,” he says “then you can’t pretend that theirs was a happy ending. Part of the tragedy was that Mack always put work first, and he always thought he knew best. It was a single-minded strength that would in time become his downfall – he absolutely refused to believe the talkies would ever catch on.” There’s a kind of rueful admiration in the way Ball then goes on to talk about Sennet before he suggests why, regardless of the copious nominations for Tony Awards after the premiere, Mack and Mabel slipped off the radar.

Perhaps it’s Ball’s own rigorous work ethic, his immersion in what he sees as his bounden duty to fans and audiences to give always of his best that makes him engage so wholeheartedly with Sennett, warts and all.

“Mack really was a creative genius,” he continues. “without his vision, the movies wouldn’t be the movies. He risked everything by leaving New York and relocating to a desert in California we now know as Hollywood. He nurtured the careers of Charlie Chaplin and Fatty Arbuckle, he created the Keystone Cops – named after his Keystone Studios – and the Bathing Beauties. He was, in those 1920’s hey-day of the two-reeler, the King of Slapstick... and when he discovered Mabel Normand, he wanted her to be his Queen.

“But – and if you listen to the lyrics of 'I won’t Send Roses' he’s really laying it out for her – the work came at the expense of everything else: relationships, tenderness, sweetness all got left behind while Mabel herself became part of that sacrifice. That kind of show wasn’t what people in 1974 expected from a Jerry Herman musical. The Vietnam War was on, and the public didn’t want 'real', they wanted froth. But musical theatre audiences have become much more sophisticated since then – mind you, they’ll still laugh at a custard pie in some-one’s face.”

He cites physical theatre group Spymonkey as the expert drill sergeants who have licked everyone into slap-stick mode.

“It’s all in the timing,” says Ball. “On the count of one – turn. On two – pick up the pie. On three – splat! And you get the laugh. Two beats is no use, neither is four – two-and-a-half is just tragic! We want to get the feel, the fun, of the silent movies for modern audiences who have probably never seen what was the wonder of that age – a new technology, as amazing as social networking on your phone is now. It mattered to Mack that everyone got it right – and it matters to us.”

If undiluted dedication was a cologne, Michael Ball would smell of it every day.

Mack and Mabel is at the Playhouse, Edinburgh from Tuesday to Saturday November 21

www.playhousetheatre.com