Getting to grips with Don Giovanni - 'It's a monster of a role'

In a big brick rehearsal room just north of the M8, cast and crew of Scottish Opera are piecing together their new production of Mozart's Don Giovanni. They've reached the end of act one and the Don's in a tight spot: he's invited a wedding party back to his place, but things get sticky when he makes off with the bride and blames her screams on his sidekick, Leporello. It's a pivotal scene, and for the baritone playing Giovanni it's a test of charisma and flash reactions: all swagger and charm one minute, guile the next, brute violence the next.

The man in the balancing act is Jacques Imbrailo, the 35-year-old South African who earned widespread admiration as Glyndebourne's Billy Budd in 2010 and again this summer (the Guardian's George Hall described his revival performances as "almost unbearably moving"). Watching from the director's chair is Sir Thomas Allen, among the greatest baritones the UK has ever produced and a veteran Don Giovanni himself. Allen estimates he's sung the role at least 300 times, and he's mouthing along to every word. Afterwards he's up on his feet, darting about the set demonstrating the Giovanni he imagines – the Giovanni he embodied so many times.

This is the fourth opera that Allen has directed for Scottish Opera. The others (The Marriage of Figaro, The Barber of Seville and The Magic Flute) have also featured baritone roles that he once made his own. Singers who work with him tend to describe his directing style as supportive and inspiring, and the results so far have been three of the classiest stagings in Scottish Opera's beleaguered recent years. With the company in a fresh state of crisis after the sudden resignation of its new music director just over a fortnight ago, all hopes will be on Allen's season opener to deliver another hit and conjure up some positive headlines.

But for the veteran singer who has shifted from centre stage to behind the scenes, doesn't it sting a bit to watch a hotly-tipped young thing take on his mantle? And for the emerging baritone trying out a major role for the first time, isn't it intimidating to do so in the presence of one of British opera's most definitive voices? Not really, and just a bit, say Allen and Imbrailo respectively.

Off-stage Imbrailo is soft-spoken and deferential. He's got the looks to play Mozart's great seducer, no question, with loose blond curls and a svelte, muscular build. His voice is powerful and expressive to match: he sounded easily commanding in rehearsal. Yet afterwards he's surprisingly tentative. "a," he says. "My reactions need to be much quicker – I haven't found that yet. I've still got to get comfortable enough to become this chameleon character."

Allen gives him a fatherly pat on the arm. "Look, you're being thrust into this at an early stage. I've arrived at my understanding of the character having built him up over 40 years." He tells Imbrailo about his own gradual evolution as The Don, describing an epiphany moment when he realised that he could save a lot of energy by "making everyone come to me" – by making a character who is so magnetic that he becomes the opera's centrifugal point. "It's got to be balletic. The point I'm trying to make, Jacques, is that the body has to change: one moment you're a monster, the next you're a gracious young man offering marriage."

Suddenly I'm a fly on the wall of a singing lesson. Imbrailo nods as he takes on Allen's advice. "Do you think there's a bit of Don Giovanni in all of us?" he asks. "Characteristics that we all share, but he takes them to extremes." It's hard to imagine the courteous, devoutly Christian Imbrailo sharing much with the lusty, guiltless Don. What does he think drives the character? "To be honest, I've changed my mind about that as we've gone along. I'd be bluffing if I said I knew who he is yet; I'm still finding out what's going to drive him to the end."

It's little wonder if Imbrailo is feeling a tad overwhelmed just now: his first child was born two weeks before the beginning of rehearsals. "I'd be lying if I said it's been easy," he says, laughing at the catastrophic timing. "I was in the middle of the Billy Budd production and was driving from performances to the hospital, getting to sleep at 3am, getting up and doing it again the next day. It's probably not the ideal time to learn such a big role, but it is the ideal opportunity to learn it with Tom."

A chance encounter and a staunch obedient streak got Imbrailo started as a singer. He grew up on a farm in South Africa's Free State, and when the esteemed Drakensburg Boys Choir gave a concert in his local town he was just one of a bunch of kids mucking about in the back of the hall. The conductor announced that there would be auditions after the concert: "my friends and I were all Afrikaans and spoke next to no English, but we dared each other to have a go. The conductor was an imposing man, almost like the Commendatore, and when he turned to us all the other boys ran away. For some reason I just stood there frozen. To a fault I've always been too obedient!" The conductor played a few notes on the piano, and being able to sing them back won Imbrailo a place at the school.

Fast-forward a couple of years and there's a clip on YouTube of a very earnest-looking Imbrailo singing in a school concert. Never mind the 90s undercut: he hurtles through Der Hölle Rache (the Queen of the Night's stratospheric aria from The Magic Flute) with fearlessly operatic attack. "It was a rough-and-tumble place – we all sang like that," he says, clearly wishing I hadn't mentioned the clip. But opera voices mature in mysterious ways. Imbrailo's slid down from that fruity treble to a tenor and eventually settled at a rich, supple baritone.

Allen's broke almost overnight; he was head-chorister one week and singing with the basses the next. "I've got a tape of me singing aged 15 or 16 and it's quite recognisably me," he says. "In fact, my voice hasn't really changed since. The customary thing for journalists to say is that it's got rougher edges now, but I'm not aware of it. It's all still there." Isn't he tempted to keep up his signature roles, then? He bats away the suggestion with a chuckle.

"Nah. I do still find it very odd to be directing rather than singing. I had a birthday a couple of weeks ago" – he turned 69 – "and realised that I still think of myself about 30 years out of synch. The energy is there of a much younger man, but the reality is, well, older. It's time to say that I've hung up my sword and my viagra tablets and that I'm leaving Don G to the new generation." He pauses. "But now that you mention it, my beef is this: there's a great case to be made for an older Giovanni. I mean, how interesting that could be..."

* Don Giovanni is at Glasgow's Theatre Royal October 15-26, then touring to Aberdeen, Inverness and Edinburgh.