Is theatre more physically demanding in your sixties? If I have a performance, I am very aware of not doing too much during the day, to conserve energy. I’ll take my dog for a walk for some fresh air and eat at about 4pm, so that I’m slightly hungry by the time I go on stage.

You tore a vocal cord playing the title role in Medea on Broadway in 1994. Are health problems an occupational hazard? Yes. That experience was horrendous. I flew to New York with a cold and went straight into a dress rehearsal where I gave it my all and did the damage. It wasn’t painful, but I couldn’t perform to my optimum.

How did you treat it? I had cortisone injections in my throat. The real treatment was rest, though. I had to sit quietly in my hotel room during the day and go straight to bed after the show. I couldn’t talk on the phone either because the timbre you use while speaking can be a terrible strain, for some reason.

Made any other physical sacrifices for your art? Loads. In Jumpers, in 1972, I had to pull a man who was supposed to be dead off the stage and I slipped a disc in my back. In Follies, in 1987, there was an 11-minute tap routine in high heels that permanently damaged my knees.

Still giving you gyp? All the time.

Green tea or your GP? I went to see a very good surgeon about my knees ten years ago. He took an X-ray and told me that he’d never seen such a bag of old rubbish in his life. But he said: “You’re functioning, you’re walking, I’m not going to do anything.” I’m touching wood that things don’t change.

And your back? I have tried everything for that. I had faith healing, I had crystal healing, I even had one extraordinary woman who came to my house, cracked her fingers down my spine and then made a huge sneeze to “expel the badness”.

Not a huge success? No. In the end the answer was conventional medicine. I had two hair-raising sessions where they inject steroids into your spine with what could almost be a horse syringe. It hasn’t cured me, but I am much better than I was. There are still times when I know thatI just have to take an anti-inflammatory and go and lie down.

Do you owe your husky voice to the smokes? I’m afraid I do. I smoke 20-25 a day. I choose low-tar cigarettes, though — my one concession.

Ever tried to quit? I have given up a few times over the years, but I have always started again. I tried hypnosis, but it didn’t work for me. I didn’t even go under. The hypnotist told me to think about palm trees; all I could think about was what a dreary voice he had. I was giving him mental notes on his delivery.

What about the sauce? I like wine, but I hate getting drunk. And I don’t like going to pubs.

Are you a gym bunny? I’m not. With my bad back and my knees, it’s the perfect excuse.

Nip’n’tuck? I had my eyes done when I was 44. At the time I was in bad pain with my back and I had lost a lot of weight because of it. I suddenly looked like a very old woman, with terrible wrinkles around my eyes. It was too early to look 64, so I thought, time to get them done.

Did it give you a taste for self-improvement? Well, I haven’t been back. I’m at the age now where I think I want to acknowledge how I have lived. I don’t envy women who look half their age. I think it’s wonderful that they do, but I’m not quite where they are at.

Did growing up in India influence how you look after yourself? I think that Ayurvedic medicine is wonderful. At Christmas, I went to a spa in the foothills of the Himalayas with my daughter, Rachel Stirling, and spent some time having treatments and massage. I’m not a great follower of anything to the letter, so I don’t stick to an Ayurvedic diet. But the massages were amazing.

Say your prayers? I am a Christian and I like going to church. Quite often I will pass a church and just go in to say a prayer. I am interested in belief of all sorts, which is probably something to do with my vocation. People come to the theatre to believe.

In Honour, your character’s husband leaves her for another woman. Art appears to be imitating life, so have you drawn on your own experiences for the part? Well, my husband walked out on me in 1990. However, this was years ago, so I’m not using this as therapy or anything.

You’re not the neurotic actor, then? I’m afraid that I am hopelessly un-neurotic, which is a shame because I’d probably be a better actress if I was.

Dame Diana Rigg is in Honour is at Wyndham’s Theatre, London WC2, until May 6. For tickets, call the booking line on 0870 9500925

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