My sexy image can be hard to live up to: Susan de Muth in bed with . . . Denis Lawson

Denis Lawson, 45, is starring as Horner in 'Lust', a musical version of Wycherley's 'The Country Wife', at the Theatre Royal, Haymarket, London. Horner is a treacherous, promiscuous, insatiable philanderer.

I BRING Horner home with me, in that lines and songs from the show are constantly going through my head all night long. Even when I'm asleep. It's always like that - these characters take you by surprise. I like Horner and enjoy playing him, but I don't approve of him. Sex does have a high profile in my own life, but I don't need loads of women like Horner - for me Sheila Gish, with whom I live, is quite enough.

Horner has dreadful bedroom manners. At one point in the play he says: 'Keeping a lady company after you've done your duty is about as tiresome as the company of a country squire.' This is not something I've ever found personally, and I'd like to have this line removed. I don't think it's acceptable to modern women, and I don't want half the audience sitting there thinking this guy's a terrible old chauvinist shit - though he is, of course.

I've never tried to be some matinee idol, but I've somehow acquired this sexy, bedroomy image. It can be quite hard to live up to, especially if you're tired and are just nipping out for a pint of milk. But an actor has to work. It doesn't bother me actually, except in terms of the profession - if people see me in that way, do they take me less seriously as an actor?

Compared with Horner, my own bedroom activities are rather tame. I have a bust of Hypnos, the Greek God of sleep, next to the bed. The bed is at one end of the room, and there's a bath at the other, which is unusual, but very relaxing. It's a lovely light room, a complete retreat when I come home after the play. You're so wired afterwards that it can be hard to sleep, and I used to go out and drink far too much. Nowadays the most outrageous thing I'll do is have a bottle of Guinness.

It's very important to me that Sheila (who is also an actor) is there when I get home and I'm winding down. Fortunately work doesn't force us apart much. We don't like that. We're very much there for each other. I always play the acoustic guitar when we're in bed, and Sheila doesn't mind. More than anything else I like to play Night Moves by Bob Seger. It reminds me of when I was a teenager. We usually drift off to sleep listening to music. Ry Cooder's score for Paris, Texas is perfect - very atmospheric and drifty.

Like many actors I do all my work in the bedroom. I learn my lines and work on the script, lying on the bed. You need to feel you are somewhere private where no one can hear you, where you can wander about, practise gestures and throw lines around and not feel self-conscious. I also do voice exercises and sing arias there and see if I can shatter the windows. I'm very compulsive about work. I always work very hard. That's what I like.

Sometimes I get too wound up and it's difficult to stop. No matter how successful you are, this is still a very stressful profession. I occasionally suffer from insomnia, which makes me absolutely neurotic. I know the price of complete exhaustion and never want to go through that again.

A couple of years ago I was doing six nights, two matinees in Lend Me a Tenor in the West End, and a television series. I wasn't getting much sleep, but I thought I could do anything. Then one night I had the most tremendous anxiety attack on stage in the first scene, a sort of monstrously exaggerated stage fright. This continued night after night until I had it the whole way through the play. When I nearly passed out four times in the course of a performance, I realised I couldn't go on. I put myself on a plane to Scotland the next day and went home for 10 days' rest.

This time round I'm being very, very careful with myself. I wish I didn't need so much sleep, but I must have eight hours. That's why there'll be no after-show partying for me for the time being. Just Sheila, my guitar and Hypnos.

(Photograph omitted)