Tonight is opening night. The red carpet has been swept and the champagne glasses polished. The press are camped outside the stage door, poised to snap the cast as we sweep out of our black cabs and into the building, wrapped in billowing scarves, with an enigmatic smile on our lips and a coffee in one hand. Once inside, we each settle into our own dressing room and run a few lines out loud while our masseurs work on our neck tension and someone with combs and pins artfully twiddles our hair. After a flick through the script, a brief consultation with our yogi and a downward-facing dog or two, a calm voice calls over the tannoy for Act One beginners.

I leave my imaginary dressing room and walk up the stairs to the Lion and Unicorn Theatre in Kentish Town where I will actually be performing tonight, in a production of Macbeth. The back door has been open and the space is mercifully cool compared to our tech/dress yesterday, when the door was shut and all the lights on all afternoon in 30 degree heat. I squeeze into the dressing room, in and out of which 13 other actors are also trying to squeeze, and find some mirror space in which to apply mud to my face from a plastic cup (the mud having been stolen from one of the pub’s pot plants, as mud is strangely difficult to come across in the middle of London in a heatwave). There is a male actor next to me smearing black eyeshadow onto himself, and the place is littered with daggers, wet wipes and fake nails. A girl is sitting on the stairs asking another girl if she should die on her front or on her back. From the theatre I hear several people humming loudly, and two other people having a very vocal fist fight, interspersed with “God sorry, did I get you?” and “can you end up further to the left when I stamp on you?” Lady Macbeth is muttering the words of her madness scene to herself, looking to an outsider every bit as mad as the character is supposed to be, and Macbeth is carefully pouring out containers of blood to be stowed behind the curtains. Macduff, First Witch and Ross are chatting on the fire escape, and Fleance is eating Quavers in the front row.

Everyone is slightly nervous because the dress rehearsal yesterday was shaky, as you would hope a dress rehearsal to be given the perennial theatre maxim, “bad dress, good show”. Most of us had moments onstage where we just wanted to punch ourselves in the face for this sloppy entrance or that dropped line or that bit of bizarrely bad acting. However, once I had been horribly murdered, I crept into the auditorium to watch the rest of the dress run and suddenly it all looked real. I stopped seeing the mistakes that are only visible from behind the fourth wall. I gasped during the fight scenes, despite having seen them endlessly in rehearsal at half the speed. Twice I was nearly brought to tears. My heart was beating faster than normal as the lights went down on our specially augmented ending. Forget what a show looks like from behind; whether it’s yoga or Quavers, it’ll be alright on the night, and in this case, it might even be bloody good.

Macbeth runs at the Lion and Unicorn Theatre until Saturday 3 August 2013. For more information and tickets visit the Lion and Unicorn’s website

Photo by Flickr user L.C.Nøttaasen under a Creative Commons licence.