Why Felicity is growing old gracefully

She is no fan of the beauty mega-industry. "Women are gullible, we have to admit it, when it comes to certain areas we feel insecure about, and how we look on a bad day. We've been told as girls that the beautiful princess gets married to the prince, and the ugly one doesn't. Your value is still how you look.

"So nowadays you go to the hairdresser and instead of just cutting your hair they're offering you all these other treatments and sort of semi-surgical things.

"And they're not real doctors, of course. What they're doing, all these thousands and thousands of people offering beauty treatments, is tuning into a new market of financially independent, but still insecure, women, who've all been told they have to do this to their face and that to their tummy - it's rubbish. We just mustn't listen to them."

Not that she has always, of course, been immune to the pressures imposed upon women, and upon actresses in particular. "In my day, there was Twiggy and everyone had to be seven stone, which was tough for lots of women.

"A long time ago, when I was 20, you had to go on a grapefruit diet and then get wrapped in seaweed. What was I doing?" She laughs that Barbara Good cackle. "Now I'd say: 'What the hell is this seaweed bollocks?' It can't possibly make you smaller! But someone says something, and you think, oh I've got to try it."

Kendal's general philosophy for good health is perfectly straightforward and, again, owes much to her mother. She stays fit because she feels stronger that way and can do things an unfit 60-year-old can't. Looking younger is a fantastic byproduct of regular exercise, but not the reason for it.

"The message at the moment, which is wrong, is: go to the gym and get fit because then you can fit into that skirt. Well that's bollocks. Go the gym, do yoga, go for a walk, because your brain will work better, and then you can deal with all that stuff life throws at you in a better way than if you're feeling permanently exhausted."

She first started paying proper attention to exercise and posture 30 years ago, but has long been a devotee of yoga - way before the yoga mat was as fashionable an accessory as the new Balenciaga handbag. Famously, her parents, Laura and Geoffrey, ran a Shakespeare touring company in India - fictionalised in the Merchant Ivory movie Shakespeare Wallah - and Kendal grew up "watching my mother do yoga as a tiny child".

"That was way before it was the hot new thing here. It was just what you did in India. People had a massage not because they wanted to be "pampered", but because it's actually quite good for you, to get the blood flowing. These are supposedly modern things to do, but actually they've been around for centuries.

"As for junk food, if I'd ever walked down the road eating anything, my father would have clouted me." For lunch today, before a matinee performance, she is having a cup of Thai vegetable soup, a cappuccino - and that's it.

Grandchildren also inspire healthy living. Kendal has two sons, 33-year-old Charley from her first marriage to actor Drewe Henley, and 19-year-old Jacob, with second husband Michael Rudman, an American theatre producer. (A little confusingly, she left Rudman for an affair with Sir Tom Stoppard, but is now back with Rudman again, though they haven't re-married.)

Living with an American, she says, definitely makes you more health-conscious: "Taking vitamins is a matter of routine to Americans. He goes to the gym three or four times a week." There are two granddaughters from her first son, aged four and six, and a spattering of greatnieces and nephews. Once a twentysomething sex symbol in green wellies and headscarf, Kendal is nowadays determined to be an active granny.

"My first grandchild, actually the daughter of my nephew, was a big baby - she's eight now - and I remember having her in the back of the car. She'd fallen asleep and I went to pick her up and suddenly thought: 'I don't know if I can.' And then I thought: 'Sod this, I'm going to be the kind of grandmother my own mother was to my sister's children and to Charley - swimming with them, taking them off on holiday'. I stepped up the exercise after that."

Well into her seventies, despite the genes, Kendal's mother suffered from osteoporosis and "just went whoosh, dried up and sort of shrunk". "I do take supplements to stop that happening to me. By the time I had Jacob, she was beginning to be really quite frail and I was so sad that she couldn't do with him what she'd done with the others."

In 1984, Kendal's elder sister Jennifer died of cancer. She implies, and it's an obvious implication, that such an event teaches one the value of time, and encourages one not to waste it. Kendal nowadays takes just one big job a year, almost always in the theatre. The ITV series Rosemary & Thyme, in which she plays a gardening detective, is "light and warm", she says, and "pays the taxman", though it also raises her profile and pulls in the theatre punters later.

She and Sir Peter Hall are mutual champions: last year he directed her in Beckett's Happy Days, and in 2003 she was in Charlotte Jones's Humble Boy at the Gielgud alongside Simon Russell Beale. "If I work any more, I start to miss the other side of life, which is being totally domestic and reading a lot of books and going for long walks." She has missed these things even during the two months of full-time rehearsal for Amy's View.

"I went to pick up the grandchildren from school yesterday for the first time in two months, and I was nearly in tears. I normally do the school run a few days a week, and I had the dog and the kids in the car, and I thought, 'Ah, back to where I like to be.' As a young mum, I worked right the way through both of my children. I went back to work when they were weeks old, and that's tough.

"I suppose what I realise now is how fast that all goes, that growing and doing the homework and stuff. You also realise that you do have time. I think as a young mother, sometimes you panic and think: 'Oh my God, these children are going to take my life away!' But they're not. When you've seen it and gone through it, you realise how much you should just enjoy it.

"I really love not being 27 and worrying about how things are going to turn out, because I know how things are going to turn out. They can be really bad, and they can be really good, and my only intolerance is for people who don't understand how precious time and life is."

And we are back on the issues of age and ageing. The Times headline was right, of course: she is ageing well (as is Amy's View). Kendal's broad assessment of this enviable state of affairs? It's part luck, part work - like everything else in a successful life.

Felicity Kendal stars in Amy's View at The Garrick (0870 890 1104).