@ Traverse, Edinburgh, until Sun 16 Aug 2015 (times vary)

On its tenth anniversary, An Oak Tree returns to the Edinburgh Festival Fringe at the Traverse Theatre. Co-directed by Karl James and Andy Smith, Tim Crouch’s play is an experimental and original piece of theatre that has travelled around the world. Over 300 actors have played the second character, without having seen or read the play before. The stage of Traverse 1 this year has so far welcomed Ewen Bremner, Jamie Michie, Aoife Duffin (A Girl is a Half-Formed Thing) and, in this performance, Sharon Duncan-Brewster (Swallow). This is a challenge for any actor, but Duncan-Brewster is no stranger to playing a role undefined by her appearance; she played C in Sarah Kane’s Crave in 1998.

Two men meet for the first time; Duncan-Brewster takes on the role of a bereaved father, who lost his child to a car accident, and Crouch plays a hypnotist who was driving the car. Acting accordingly, with cheesy grin and jazz hands, he breaks in and out of character, alternating between the fictional performance, and the performance of Crouch and his actor. The piece is literally being created before you; even Crouch can be as shocked as the audience at what happens next.

Bringing together art and reality, it can be perfectly described as a magic trick. Inspired by Michael Craig-Martin’s 1973 installation An Oak Tree, it’s about what exists in the mind. Just like a glass of water, a girl can turn into an Oak Tree, and an actor can turn into a character as they step on the stage. We hear the actor being given instructions, but what amazes us is their ability to dive into this character – we are hypnotised ourselves during the performance. Unlike an ordinary visit to the theatre, we are constantly reminded this is someone acting, and we are immersed into analysing their performance.