“For me, the dream collaboration would be a toss-up between Marilyn Manson and Tom Waits,” says Kate Mullins, after breezing through an evening of feel-good classics for an audience of tea-swigging swing devotees. Well there’s a turn-up.

The Puppini Sisters – also comprising Stephanie O’Brien and Marcella Puppini – are a modern equivalent of wartime boogie-woogie combo the Andrews Sisters, with a twist: they’ve been described as ‘swing punk’ and have included indie classics like ‘Panic’ by The Smiths in their re-interpretive repertoire. But then they have also been working closely with Michael Buble recently. Are they ok to like? A guilty pleasure? Or an experience to be avoided at all costs?

You can’t help but be impressed by the talent, to be honest. The classically-trained trio have voices like angels – best observed on their earnest run-through of ‘Oh Holy Night’, the only carol of this Christmas show. They’re also gifted musicians, O’Brien sawing furiously on the violin, Puppini wheezing away at the accordion and Mullins providing both witty asides and some useful instrumental breaks with her blow-organ - the melodica - and plinky-plonk percussion (“I think I need to be taken more seriously for my glockenspiel playing.”)

This being a festive special they mix up the tunes, throwing in classics from various eras (a string-laden version of Wham’s ‘Last Christmas’, Mariah Carey’s ‘All I Want for Christmas’ and your old-school ‘Winter Wonderland’) to less seasonal material. There’s an undeniably moving version of ‘Moon River’ – from their upcoming ‘Hollywood’ LP – and a frenetic swing stab at Beyonce’s ‘Crazy in Love.’

But are they cool? Well, much of the straightforward old-school stuff is done with a definite wink – on the gay Christmas wish-list they’re up there with Kylie and KY Jelly – and have an edgier past. As Mullins reminds me after the gig, they did a lot of work with retro electronica chap The Real Tuesday Weld years ago, while she personally is currently “collaborating with the people I was in a metal band with,” which would undoubtedly surprise her more sedate fans. What’s her contribution there? “I hate to say that it’s ‘ethereal’ vocals, that makes me sound like Evanescence, and I’m NOT a fan of Evanescence.”

Which is certainly a plus point. Has she ever pushed the Puppinis in a heavier direction?

“We did do a cover of ‘Welcome to the Jungle’,” she recalls, “and it nearly worked.” The problem for The Puppinis – who generally come up with radical new arrangements – is that the Guns ‘n’ Roses original was already pretty jazzy. “Listen to it, it’s kind of got an element of swing to it, so it didn’t actually sound that different from the original. So we thought ‘oh bugger that, let’s do something else.’”

And Buble? Sadly he’s no secret rock ‘n’ roll animal by the sound of it. Indeed, all the female attention is proving a bit bloody awkward.

“He was telling us the other day, ‘as soon as I got married, having this ring on my finger, it’s just making it worse’ – girls have been throwing themselves at him even more. He’s become unattainable.”

Metal-fan Mullins must find his stuff a bit wet though, surely? “I’m full of admiration for him, he’s like the modern day Bing Crosby, to be absolutely nailing what he’s doing,” she insists. “He doesn’t care if people like him or not. He’s having so much fun.”

And so, clearly, are The Puppinis. All power to their elbows.

Words by Si Hawkins