The film version of Rita Hayworth and Shawshank Redemption initially flopped back in 1994, but since then, the story of Andy Dufresne’s battle for survival in a tough penitentiary has wormed its way into the most revered echelons of pop culture. And now it hits the stage at this year’s Fringe, where Stephen King’s novella has been adapted as a play, boasting an all-star cast and a high profile director in Lucy Pitman-Wallace (formerly of the Royal Shakespeare Company).

‘This isn’t an adaptation of the film; Owen O’Neill and Dave Johns have created an essentially theatrical experience,’ says Pitman-Wallace. ‘When I read the book, I found that the character of Red, played by Morgan Freeman in the film, is actually an Irishman. Seeing these differences frees you up as a director to take things in a fresh direction; after all, the play, the book and the film are all three different things.’

So why should it be that The Shawshank Redemption is a story that the public simply can’t get enough of? Pitman-Wallace has her own ideas about the enduring appeal of King’s story.

‘What Andy does in prison is to do with finding ways of staying sane in a terrible situation. He uses books, movies and sculpture, he even makes up a prayer. His method of survival is a perfect metaphor for the creative process, and demonstrates the importance of storytelling in our lives,’ says Pitman-Wallace. ‘It’s something that really speaks to my own experience as a theatre director. I worked with Seamus Heaney and he used to talk about how storytelling was vital to the mental health of the nation. I see that idea in this story.’

Taking a break from rehearsals in baking hot London, it’s also clear that putting the show on may pose a few obstacles to Pitman-Wallace. This production follows a popular Fringe formula (Twelve Angry Men, One Flew Over the Cuckoo’s Nest), with an ensemble of recognisable actors, ranging in this instance from Omid Djalili to Ian Lavender.

‘We got very interested in the mixture of stand-up comedians and actors, which is almost like some kind of social experiment and can be very challenging at times. For example, Jack (Monaghan) is a young man from drama school, and is a conventional actor compared to, say, Terry Alderton, who is very much versed in stand-up tradition. So you have a cast from very different comic and theatrical backgrounds. One, I won’t say who, said to me “I’m not a stand-up, I’m a comic actor”. They all come from different backgrounds, and they all prepare themselves in different ways, no one is less valid than the other. The result is an amazing explosion of energy.’

Getting your cast out and about is a Fringe tradition, but Pitman-Wallace has no plans to frog-march her ensemble cast up and down the Royal Mile handing out flyers.

‘It’s an interesting idea, but I’m not sure I’d ever want to let them loose on the public in quite that way!’

Assembly Rooms, 0844 693 3008, 2–25 Aug (not 12), 4.50pm, £16 (£12). Preview 1 Aug, £15 (£11).