KATHERINE MACALISTER, below, gets down and dirty with the puppet stars of Avenue Q.

I think you’re horny,” Trekkie Monster from Avenue Q says rubbing himself while I sit, notepad in hand, interviewing him, trying not to act like Mary Poppins.

“Do you want to come back to my room after this,” he continues, stroking away like a teenage boy on Viagra.

Bearing in mind that Trekkie is a puppet resembling Animal from The Muppets and that most of what he says is utterly unprintable, you’ll realise why the interview isn’t going according to plan.

Plus Trekkie isn’t really into talking. He prefers staying at home and watching adult TV. The two other puppets I’ve been sent to interview – Kate Monster the primary school teacher and her new boyfriend Princeton – are busy discussing getting down and dirty live on stage.

It’s hard to know where to begin with Avenue Q. It’s billed as the musical for people who don’t like musicals, or the adult version of The Muppets, even though it’s not The Muppets.

But it’s futile to resist or underestimate the enormous popularity of the Avenue Q show, and once smitten always smitten, judging by its fans who return over and over again to the West End to watch this hilarious musical.

Except that now it’s touring and coming to Oxford’s New Theatre, and if you haven’t caught on to the Avenue Q phenomenon, jump on board while you can, before it steamrollers you and drives on by.

To set the scene, Avenue Q is all about the lively and off-the-wall puppet characters living in a downtown New York street. The musical is witty, rude, mischievous, politically incorrect and extremely funny, tackling thorny subjects such as dating, racism, being gay and finding your purpose in life, while winning a Tony award in the process.

To introduce the characters, Trekkie spends most of his time in his room watching porn, and only goes out when his broadband connection is down. Kate Monster has managed to talk Princeton into going out with her, but ask about whether they’ll be moving in any time soon and Princeton nearly keels over.

“We’re taking it slow,” says Kate smiling, “but who knows what the future holds.” Princeton it seems has other ideas, mentioning Lucy The Slut on more than one occasion, who has “great t***”.

Ask about their simulated sex scenes and he immediately objects: “It’s not simulated, it’s full frontal, live on stage.” “Which is a little embarrassing,” Kate Monster chips in, “but part of life. But it’s a very honest show because we’ve all been there.”

So do you all sing? “Of course we sing, it’s a musical,” Trekkie grunts rudely. Ploughing on, I ask him what’s been his best moment of the tour so far. “Meeting Miss Wiltshire last week. She was dirty,” he barks. You get the picture.

The puppets are attached by hand to their human counterparts live on stage. The expectation is that once you get used to their doubles you disregard the people fairly quickly. So is that something the actors mind: “No, it means I’m doing my job properly,” Princeton’s Adam Pettigrew says. “Once we got the parts they sent us all to puppet school to learn the right technique and emulate that transatlantic muppet twang.

“So for the show I think of myself as Princeton and give him a life. So yes it’s dirty but it’s tongue-in-cheek and that’s what people like. I’m not just a pretty face,” he smiles.

Does that mean he slips into Princeton’s persona even when not on stage? “No, although there’s always a bit of Trekkie on the tour bus,” Adam grins. “But I’ve got it down to a fine art, although we still get people in the audience shouting out ‘I can see your mouth moving’,” he says laughing, as he packs up ready to move on to the next theatre.

But before I’d had the chance to escape, I felt a familiar paw on my back and that unmistakeable rubbing motion begins again. “Did I tell you how horny I am?” Trekkie growls, “let’s get a room.” Taxi?

* Avenue Q runs at Oxford’s New Theatre from Monday, April 23, through to Saturday, April 28. Call the box office on 0844 8713020.