Who hasn’t heard of the Chinese martial art Kung Fu or that great British tradition, the pub crawl? But Pub Fu? That’s a new one. However, this amalgamation of pastimes is artfully demonstrated in The World’s End starring Simon Pegg and Nick Frost.

“It was fantastic – I got to fight 10 men at once and didn’t get hit,” says bearded Frost, 41, recalling the scenes in which he and co-stars Pegg, Martin Freeman, Paddy Considine and Eddie Marsan release their inner action men when a pub crawl takes an unexpected turn.

On hand to assist was stunt co-ordinator Brad Allan, who’s worked with martial arts legend Jackie Chan for years. “He’s quite serious, but sometimes you’d see him laughing at the monitors at something you’d done and you’d feel amazing,” says Essex-born Frost.

The British sci-fi comedy is the third film in Pegg and Frost’s Blood And Ice Cream trilogy, following 2004’s zombie romcom Shaun Of The Dead and 2007’s cop comedy Hot Fuzz. The latest story begins in 1990 in the suburban town of Newton Haven when five teenage boys celebrate leaving school by attempting, and failing, an epic pub crawl.

Twenty years later, the ‘five musketeers’ have grown up and moved on, with the exception of immature and irrepressible ringleader Gary King (Pegg), who becomes hell-bent on reuniting the gang and tackling the 12-pint ‘Golden Mile’ again.

Unenthused, the others go along with his plan but soon realise something odd is going on in their home town, and the pub crawl begins to unravel.

“It’s a bigger proposition for us than the earlier pictures,” says Pegg, 43, sitting next to his long-time friend Frost.

As with the two earlier films, Pegg co-wrote the script with Edgar Wright (who has directed all three) and reveals that the pub crawl element “partly came from a script Edgar had toyed with at a young age”, based on one he and his friends attempted as teens.

They didn’t make it past pub six, but that sense of it being a quest stuck with Wright. This time, though, the drinking marathon is just the beginning.

“When you go back to your home town, you experience this simultaneous feeling of familiarity and alienation and you can’t put your finger on what it is.

“It looks the same but it isn’t – and that’s because you’re different, it’s not different,” says Pegg who hails from Gloucester but now lives in London with his wife Maureen and their daughter Matilda.

“We thought it’d be funny if [in the film] the reason it feels different is if it had been taken over by alien robots.”

He and Wright began writing the script in mid-2011, a process he describes as “swift”.

“By now, we understand each other’s way of working and we’re on the same page perhaps more than ever,” says Pegg, adding that it didn’t take long to hone his irritating character. “Edgar and I joked about how in reunion films, like 1983’s The Big Chill, there’s a corpse because someone’s just died. In The World’s End, Gary basically is the corpse.

“When he turns up to talk his friends into doing the ‘Golden Mile’ it’s like they’re seeing a ghost from their past.”

The pair couldn’t have had a better time on set. “We just hung out,” says Frost. “I wish I could tell you some story where we all hated one another but we just laughed a lot.

“It was that thing where you get home and you have your shower and you get your bag ready for the next day and you think, ‘I can’t wait to get in’, and that’s a rare thing in any job.”

It wasn’t all laughs though. “We all had a moment in the film where we’re angry or upset or sad and it’s serious acting, not just goofing around,” says Frost. “But it all felt very supportive.”

Among all this testosterone, former Bond girl Rosamund Pike, who plays Freeman’s sister, managed to hold her own.

“She gives as good as she gets, and throws herself into it,” says Pegg.