With giant lights beaming down on the set, it's just about the warmest forest RT has ever visited, but it's far from the stuffy environment we expect from rushed indie film productions -- more for the atmosphere amongst the crew than the temperature on the soundstage. Horne and Corden chat jovially in-between takes, and director Phil Claydon seems keen to ensure the mood on set is as light as the material. Everyone seems to be having a great time working on a piece of light-hearted entertainment.

Buring behind the scenes.

But there is more to the film than just ludicrousness of the premise and the first two thirds of the title, its stars say. "I think it offers a lot more than the title implies," says Corden. "And it's predominantly about two friends on a weekend and what happens for them." Agrees Horne, "It's part road-movie, part buddy-movie and there's some horror in it as well, so it's a great balance. It was the script, first and foremost, that made us want to do it."

As the pair's first attempt to lead a big-screen comedy - though Corden, of course, has spent time as part of ensembles in the likes of The History Boys or as supporting characters - it may well mark an important step in their careers, too. The tremendous success of Shaun of the Dead led Simon Pegg from Brit TV comedy roots into big-budget Hollywood movies, and it's hard not to make comparisons between the two. Both feature stars of British TV comedy series' making their big-screen debuts as the leads in comedy horror films.

Colloca gets mad and apparently electrical.

For them, though, the project was simply an opportunity to work with interesting material. "We've done work either side of Gavin & Stacey that stands up," says Corden. "It was never a case of 'Ooh, here's a chance to show what we can do.' We thought of it as a chance to be involved with something that's really good.

"It's odd because on no level was this written for us. The script was written before we were involved, but if we had approached [the writers] Paul & Stuart and said, 'write a film for us,' I don't think it would have been vastly different. Certainly in the characters - it felt really perfect, and the perfect time to do it."

Corden, Horne and Buring.

The truth is that the film probably will have to pitch somewhere close to perfect to really work with wider audiences in the way that Shaun did. The novelty of the title has worn off quickly, and the project has even attracted attention from anti-defamation leagues who are failing to see the humour. Shaun-esque success lies in one direction, but another Brit comedy double-act, Mitchell & Webb, saw their big-screen debut, Magicians, sink without a trace -- unless the film can attract word-of-mouth support for its quality and comedy there's a real risk it'll head in the same direction.

Fortunately, a few months after our visit, RT previews 10 minutes of the film in front of an engaged FrightFest crowd. It's a showreel for the film that hasn't really been done justice in the trailers that have emerged publicly to date, and it has the audience in fits of laughter throughout. That familiar Horne/Corden sense of humour is there, and the fish-out-of-water fumblings of the pair trying to get to grips with their situation are genuinely funny. If the finished product can maintain this level of belly-laughs for all of its ninety minutes, we may well be in for a treat.

Lesbian Vampire Killers releases in the UK on 20th March following a premiere screening at SXSW festival in Austin, Texas. US and AU release dates are to be confirmed.