28/05/2012 13:18 BST | Updated 28/07/2012 06:12 BST

Heading to HowTheLightGetsIn

I have been invited to take part in HowTheLightGetsIn, the music and philosophy festival, at Hay on Wye on 8 June. At first I said thanks very much but no, as I presumed they meant some kind of talking event, which would have filled me with dread, but they said I had the freedom to think of something creative.

So I asked Kingsley of The Chapman Family, my favourite band in years, if they would like me to paint a massive live backdrop for a performance by them, and they said yes! We figured out the logistics as best we could, leaving the painting side of it to gather fire at the back of my mind, so that I could be free to improvise on the day.

I'm going to paint for 12 hours, from 10 in the morning, till 10 at night, and then the band come on stage and perform. They will play new songs from Cruel Britannia, and a Morrissey cover too, which sounds deeply beautiful. I'll take lots of paint, some big brushes, and a ladder. They're amazing live, so I hope I'll have made something that does them justice by the 10 o'clock deadline, and then I can enjoy the band.

I tend to make tiny paintings these days, so it's quite an adventure to make something on this massive scale. I would imagine I'll be totally consumed, melting into the piece, with little time for self-criticism.

In a drama class, when I was 17, we were asked to go and see Mr and Mrs Andrews, the painting by Gainsborough, we had to figure out the truth based on what we could see. From then on I would look to art to enrich the portrayal of the characters I was playing. For Regina in Ibsen's Ghosts, for example, all my relatives were imagined from Munch paintings, and other Nordic art. Of all the many creative pursuits I have worked in throughout my life, painting is the one that makes the most sense to me, and I am happy with what I try to achieve within it.

I always thought when I was a child, that I would write a novel based on my life, I told my mum that I was going "TO WRITE IT ALL DOWN", and that's what I've been doing with my paintings, in a way. Sometimes I want to paint messy thick oil paintings with my hands or a knife, and at other times I specifically want to paint a person, with more detail.

There's a lot of interesting things happening at the festival, I'm hoping to see Camille O'Sullivan, she does a great rendition of Nick Cave's The Ship Song, and I'd be interested to catch James Lovelock, Diane Abbott, Brook Magnant, Peter Tatchell, and Suzanne Moore too. I'm looking forward to having a pint of cider, collapsing in the sun, and having a giggle with dear old friends.