The truth behind Daniel Radcliffe's Swiss Army Man farts, revealed

Whether or not Swiss Army Man, and Daniel Radcliffe's majestic performance within as a farting corpse, becomes an indie hit; there's no doubting it's had quite the journey to screen.

A thrill ride from its Sundance premiere, which sparked audience walkouts due to its fart-heavy content, to its inventive promotional campaign; which has offered fans the chance to play with Daniel Radcliffe's corpse, as well as take selfies with live Daniel Radcliffe next to dead Daniel Radcliffe.

The film sees Paul Dano as a young man stranded on a deserted island, about to end it all before he spots a flatulent corpse (Radcliffe) lying on the beach, utilising his gas to propel himself to the mainland before embarking on an adventure through the wilderness with his newfound companion.

And, unsurprisingly, it had a production just as a delightfully bizarre as everything that's happened since. Speaking to GQ, Radcliffe revealed how the shots of Dano's character riding Radcliffe's corpse to shore, powered by farts, were achieved; a sequence which can be glimpsed in the film's trailer.

"Jason Haima, who's our makeup chief... he made a prosthetic, uh, butt that had a pipe in it that you could blow air through," the actor stated. "So that's how that worked. I don't wear the prosthetic butt. The prosthetic butt is cast and modeled on my butt, and then they film on that one really close in."

Which, yes, did involve getting a butt mould done. "You have to get your d*ck and balls out of the way," Radcliffe notes. "It involved covering me in a sort of liquid that then turns to a solid. It's actually not too bad on the hairs, but you do want to keep your junk out of the way."

Another sure mystery for audiences will, of course, be the audio source of all those farts. Apparently not from Radcliffe, as he jokes: "I definitely can't fart on cue. That is beyond me. They were all done later."

"The directors basically announced if anyone wanted to just go over to the sound recordist, Steve, and fart, he would record it and they would try and put it in the movie. I think they only ended up with, like, two, one from Paul Dano and then I believe our editor has a good one in there as well."

Radcliffe also spoke a little about the severity of reaction to the film, and his own confusion on the numerous Sundance walkouts. "The farting didn't even enter my head as being a weird thing," he said. "I was really quite taken aback when we sound mastered it and it caused such a weird reaction in some people. I can understand it being not for everyone, but controversial? It's not like we're making a massive racist remark. It was very strange to me but also kind of entertaining."

"I remember there was one tweet—I'm not on Twitter. I don't get involved," he continued. "But I did get sucked in over that period, and there was one tweet that did get under my skin, because it was a guy that was all p*ssed off. He hashtagged one of his tweets #makebettermovies, which I was just like, f*cking—it's from a man who's never made a movie! The sh*ttiest film you've ever seen has had such f*cking hard work put into it! You can't say sh*t like that."

Swiss Army Man hits US cinemas 1 July, with a UK release date yet to be announced.