Perfect pacing and authentic actors give Graham Eatough’s How To Act for the National Theatre of Scotland at Summerhall a unique shine.

The audience don’t even know it, but the script is wrapping them around its little finger, expertly exploiting their most basic assumptions of what is real and what is false.

A major caveat beforehand. This production simply can’t be analysed without revealing some of its most fundamental secrets, lessening the impact it will have for someone yet watch it unfold. You have been warned.

Robert Goodale assumes the identity of Anthony Nicholl, a world-renowned theatre director, here to give a masterclass on the hidden key to acting. He has an instantly intriguing demeanour, moving about the stage barefoot with a mysterious posture. His speech is rambling yet composed, giving the sense of someone who really has amassed so much knowledge he can’t articulate it all.

He starts off speaking about ‘truth’, and how it is central to giving a genuine performance. You must believe what you are doing is real, 100% immerse yourself in the setting. This comes back to bite him, as his own denial of reality is exposed. Beautiful story arc, almost poetic.

Nicholl’s student for the class is Promise; a young girl, eager to hone her acting ability. Jade Ogugua delivers a positive, likeable character – leaving the audience completely unsuspecting of her true motives. Very well done.

Someone walking in completely blind could be seriously fooled that this is a genuine director, and genuine student. That’s the key to this performance – you assume these two people are peering into and analysing the world of acting, rather than partaking in it themselves. You let your guard down, leaving yourself unprepared for the twists to come.