In the comedian’s arsenal, a lack of shame can be a potently funny tool. And in recent years few comedians have used that weapon better than Rich Fulcher. Known to most as jelly-brained zoo manager Bob Fossil in The Mighty Boosh, a role that required him to wear a gut-bustingly tight baby-blue safari suit, he’s now branching out into drag as Eleanor, an ageing super-groupie who’s slept with the best of them from Jagger down. ‘She classifies herself as the world’s greatest groupie,’ explains Fulcher. ‘She put the wood in Woodstock. She spans the generations. She gave Radiohead. She’s been with most groups on the road.’

Fulcher moved to the UK over two decades ago when his eccentric brand of humour began to strike a particularly English chord. When I catch him he’s in his US homeland promoting An Evening with Eleanor, the Tour Whore and staying in an LA hotel room alone, though he doesn’t demur from the suggestion that he might go method. ‘I think you might see me in the tabloids before the festival hits. Look for me: Eleanor with Tom Cruise.’ In Fulcher’s Fringe show, Eleanor will be talking about a life lived among, and under, rock stars of varying fame. The main aim is educational by instructing lesser groupies in the ways of the ‘fuck-o-system’.

‘You know when actors get a little old, they’ll start their own acting school? Well, she’s founding a groupie academy to help young women, er, succeed on the road with bands.’ What advice does this academy dole out? ‘Loads of tips, about how you can’t just have sex with anybody in the band; there’s an evolution. She calls it the ‘evolution of fuck’. You start out with the drummer, because he’s like an ape, just banging sticks on a drum. And then you move up to the bassist, because he has the opposable thumbs. And then the lead guitarist, he’s dexterous with all his fingers. And then finally, the singer, because he can talk. So, little things like that, you learn about, from her.’

A man in drag acting the part of a lascivious woman is, in the canon of English comedy especially, a well-worn gag. ‘I think [the British] embrace it more, the mild sexual confusion,’ he says, well aware of the history of the joke. What distinguishes Fulcher’s act is his willingness to take it to new limits of excruciating awkwardness. Very little of Eleanor’s shtick is cabaret-style innuendo. Instead she goes straight for the jugular, using her drawling come-to-bed accent to ensnare many unwitting celebrities.

In her regular interview assignments for MTV, she’s more likely to ask up-and-coming bands about their favourite venereal diseases than their musical influences. ‘I’ll interview young bands; you know the types: they were all in the same history class in university and their legs are like pole-vaulting poles. And they’re really young and they know who I am but they get lost and they get kind of sexually confused. Especially when I become predatory. There’s a slight confusion there, and that’s where I love doing it because it makes me feel powerful for once in my life.’

Fulcher ends this last statement with some maniacal laughter. At the heart of what makes Eleanor so uncomfortably funny is the obvious pleasure that Fulcher derives from inhabiting such a crassly sexual character. It begs the question, is he just dressing up for comic effect, or is there something more perverse going on below all that make up? ‘No, it’s just, er, it’s a natural thing to be Eleanor, I feel, as a guy,’ he says, struggling to put the lid back on that can of worms. ‘The whole character started out when we were off our minds on the Boosh tour bus and I was riffing. I would say [puts on Eleanor’s voice], “Hello, who are you?” And they [Noel Fielding and Julian Barratt] would go, “What’s your name?” And I’d say, “Eleanor … where’ve you been all my life?” And then Julian put these glasses on me, and it just sort of evolved naturally.’

You can imagine the claustrophobic existence aboard a comedy tour bus leading to jokes or routines being appreciated simply through the boredom of being constantly on the road. But not Eleanor. ‘Everyone kept saying, “You ought to do more stuff with that; you ought to use that as a character”. Eventually it went into a Boosh episode, the eels one.’

Eleanor and Bob Fossil are not Fulcher’s only Mighty Boosh characters. Particularly memorable from the three series of the TV show were his turns as Tommy, the former zoo owner who became half-cheese after overindulging in dairy, and Lester Corncrake, the blind, white jazz musician who believed he was black. Though it was through the violent mood swings, bizarre dance moves and other flamboyant eccentricities of Bob Fossil that Fulcher was most instrumental in the phenomenal success of The Mighty Boosh. He has to cast his mind back to the mid-90s to remember how this relationship began.

‘Well, I was in a three-man improv group,’ he recalls, ‘doing an improvised university lecture called Modern Problems in Science. We played professors, and would ask the audience for an absurd scientific hypothesis. People would say the most bizarre things like “Czechoslovakia can be mailed” and “the centre of the universe is a giant baboon named Andre”, and we’d have to spend the hour class proving that.’

With the other Modern Problems members leaving to pursue more serious paths, Fulcher struck out to find a new show through the now defunct satellite TV comedy channel Paramount UK. ‘I was just walking around, literally going from desk to desk, saying, “Are you doing any shows? Are there any shows you’re doing that I could do?” There was this one sketch show going on called Unnatural Acts. They already had Julian on board, and Julian got Noel involved. That’s how I met them and we formed our own little cabal. They had already started doing this whole routine where they were zookeepers. It was kind of a double act thing they were working with. So they’d go, “We’d really like to do this zoo thing, and we want you to be its general manager. What would you think of that?” and I’d go, “Yeah, just get me the tightest fitting suit you can and I’ll be there. Just crowbar me into that suit”.’

That suit became Fulcher’s calling card, a symphony in blue polyester that strained tantalisingly across the belly. How small was it? ‘Extra small, I think. I tried to shrink it every time I washed it. But I try not to wash it. I’m against that. The suit can stand up by itself.’ It’s hard to imagine what Fulcher casual would look like. What does he wear when he’s got a night off from being Eleanor? ‘There’s no room for anything else. It’s almost like Eleanor has her own steamer trunk full of clothes, and Rich Fulcher has just a tiny bag. She’s very demanding. She’s quite a diva. And she’s violent sometimes. She will strike me about the face and neck. But, the Rich Fulcher line is basically torn jeans and some semblance of a shirt. Usually with stains on it. I’m thinking of having stains in my own fashion line.’

When he’s spent enough time subverting sexual norms, where will Rich Fulcher be taking his stained clothes and blurred gender boundaries after the show? ‘I’ll be lying around the tent, waiting for any comers. But, you know, Eleanor will be sweeping in and out of the comedians; she does quite well with them. She’s climbed Adam’s Hills before. She gave Brendon Burns. Oh, and she even drank Bill’s Baileys.’

Rich Fulcher, Udderbelly’s Pasture, Bristo Square, 08445 482 252, 21–30 Aug, 11.30pm, £13–£16 (£11.50–£14).