Longest-running American musical on Broadway, longest-running musical in West End history, serial winner of Tony, Olivier, Bafta and Academy awards, and a Grammy: Chicago is a statistician's dream-ticket, a box-office-busting phenomenon that continues to pack theatres to the rafters, with its racy tale of cell block chicanery and skulduggery in prohibition era America.
The David Ian Productions' UK tour of Chicago rolls into Derry-Londonderry shortly for a week-long sojourn at the city's Millennium Forum (October 22-27), and is currently playing to hugely enthusiastic audiences at the Grand Opera House, Belfast.
Spearheading the show are former Hollyoaks and Strictly Come Dancing star Ali Bastian, in the lead role of slinky chorus girl Roxie Hart, and Stefan Booth (whose credits include Eastenders, The Bill and Dancing on Ice) as Billy Flynn, her slick celebrity lawyer.
Both actors have been to Northern Ireland before, Booth with ITV's Dancing on Ice tour, and Bastian as part of Strictly's arena extravaganza. Booth's appearances at Belfast's Odyssey Arena left an indelible impression on him. 'The crowds were insatiable,' he remembers. 'It was just, like, the deafening noise from people cheering when we all came out. I've still got it in my ears now. It was just fabulous.'
Booth joined Chicago directly from finishing a stint in the BBC's Eastenders, where he played Greg Jessop, husband to Jo Joyner's Tanya Branning. Despite the easy lure of television celebrity, Billy Flynn is, says Booth, 'a dream role for me, a massively big thing'.
He had, as a consequence, no qualms about swapping Albert Square for the bump and grind of touring this production of Chicago the length and breadth of the United Kingdom. The reason for Booth's enthusiasm is simple: for him, nothing quite equals the adrenaline-shot of daily live performances before a theatre audience. Compared to that, the close-focus, quick-take culture of a modern soap opera set can seem a relatively clinical environment.
'We've been on this tour for nearly ten months now,' Booth says. 'But every night, once we've warmed our voices, and we're stretched and ready, it's just an electric show, it really picks you up. There's something quite special about Kander and Ebb's score, and there's something incredibly special about the band we're working with.
'They're amazing, the most talented bunch of musicians I think I've ever worked with. When they start playing, this alchemical process just starts up. You can feel the energy coming out from behind you. And you can almost feel a swell as the audience go "Oh, that music!" You can feel something bubbling up right in front of your eyes.'
Co-star Ali Bastian is in total agreement. 'Absolutely out of this world,' is how she describes the 11-piece pit band at the core of the 50-member company which is touring this Chicago production. 'Singing on stage with that band behind you is such a great feeling.'
Booth is at pains to point out that in terms of subject-matter, Chicago has if anything grown in relevance since its Broadway premiere 37 years ago, and that the show has striking contemporary resonance.
'When you think of the OJ Simpson trial, and the glamorisation of celebrities, whether they're criminal-minded or not,' comments Booth, 'Chicago still has its finger on the pulse of modern-day society. Look at the storyline itself. Two women in jail, getting acquitted for murder, though blatantly guilty, and owing that to a lawyer who's a silver-tongued manipulator.
'You see stuff in the press every day, where people are spinning negatives into positives, and swaying the public. There's a massive relevance to today in Chicago. And there's some really dark undertones to it that I really enjoy playing on a personal level. They take me far away from the romantic leads that I'm used to playing.'
Both Booth and Bastian are mindful of the fact that some massive stars of stage and screen have played their parts before them. David Hasselhoff, Richard Gere and Jerry Springer have all been Billy. Bastian, meanwhile, has a veritable coven of ex-Roxies peering vampishly over her shoulder: Ute Lemper, Liza Minnelli, Denise Van Outen, Brooke Shields, and Renée Zellweger among them.
Does Bastian ever feel intimidated by the glittering stars who played Roxie before her? 'I'd be lying if I said I didn't feel a sense of that when I started,' she responds, thoughtfully. 'But at the same time I came to a decision to not watch all the videos, not watch everybody else. Just approach it like I'd approach any other job really.'
And what of the classic Bob Fosse choreography in the productoin? It is, presumably, a bit of a breeze to somebody who, like Bastian, has braved the intense media scrutiny and exactingly high technical standards of Strictly Come Dancing?
'I wouldn't say that!' she chuckles. 'It's very different. It's really that old-school style of jazz, all very slick and stylised. And for me it's not partner-dancing, so I'm pretty much on my own, with nobody to put me back on if it goes wrong. It took a little bit of getting used to. They trained us really hard for it.'
So how exactly does a leading lady such as Bastian survive ten months and more of an all-singing, all-dancing, all-action show such as Chicago, playing six days a week, with the seventh designated as a travel day for getting to the next venue?
'I just have to rest a lot!' laughs Bastian. 'It's an exercise in pacing yourself, really. I've been living a little bit like a hermit for the last year. You don't see me out much. Really the whole day's about gearing up towards the show in the evening.'
For Bastian, however, the hard yards eked out living the life of a travelling player are richly rewarded by the show itself every evening. 'Every night, without fail,' she says, the thrill of anticipation is there again, as houselights dim, the band strikes up, and the curtain rises on another hummingly expectant audience.
'The moment the music starts, I get covered in goosebumps,' says Bastian, smiling. 'It's just the most amount of fun, a really, really exciting show to be part of. Nothing quite beats the buzz of live theatre, I think. You just get that immediate feedback from an audience that's amazing.'
Chicago runs in the Grand Opera House until October 20 before moving to the Millennium Forum in Derry~Londonderry from October 22-27.