One word describes Dame Diana Rigg: formidable. Not only does she, at the age of 69, still rise to the considerable challenge of playing major roles live on stage, but she also has a grand manner that brooks no contradiction.
As she prepares to play the aristocratic Madame Ranevskaya in Anton Chekhov's 1904 classic, The Cherry Orchard, at Chichester, I meet her in a quiet London bar.
With her wide eyes, rich speaking voice and cool elegance, Rigg is instantly recognisable. Most of her fans think of her as Emma Peel in the classic 1960s series The Avengers, a show that still regularly tops polls of the sexiest television series ever.
Nowadays, she's traded in Peel's trademark leather catsuit for fashionable beige and grey cashmere, and her karate chops are purely verbal, but she retains the lively self-assurance of her most famous creation.
Surprisingly, she's never done a Chekhov play before: why is that? "Well," she laughs, "apart from a couple of memorable exceptions, I've always found that the way we British do him is infinitely dull. Chekhov described his plays as comedies, but I have seldom had a belly laugh or even a titter." advertisement
Rigg was turned off the Russian master early in her career.
When she started at the Royal Shakespeare Company as a humble "walk-on" aged 21, its supremo Sir Peter Hall "organised lessons for our benefit - voice lessons, singing lessons and movement lessons. And lessons in Chekhov, given by Michel Saint-Denis, who was his greatest exponent."
Given that Saint-Denis was a theatre legend, this must have been a treat. "Well, it wasn't," she replies crisply. "It was an absolute nightmare because he had a blueprint in his head of how Chekhov should be played.
And so you weren't allowed to do anything spontaneous: wait, count to three before you move. Or, no, you take exactly five steps. So it fairly put me off - for 50 years."
Now Rigg has agreed to do The Cherry Orchard because she thinks highly of Mike Poulton's new adaptation, which mixes laughter and tears in equal measure, and because of the rest of the cast, which includes Maureen Lipman, Frank Finlay and Jemma Redgrave.
"It would be nice to take the whole cast and rent a dacha in Russia," says Rigg. "You would get that feeling of isolation.
And experience that slightly agoraphobic feeling of people being pressed together and how, as a result, you know each other terribly well. And bounce off each other: rude one minute and loving the next."
Alas, Chichester's budget won't stretch that far, but Rigg is conscious of connecting with the different sensibility of Russian culture.
"They love crying. And I cry. I was on the point of tears when the Red Arrows did their fly-past [on April 1, the 90th anniversary of the formation of the RAF]. It's so moving if you think of all those lost lives, the 19-year-olds who were killed during the war."
Crying apart, Rigg comes across as distinctly unsentimental, as can be seen in her attitude to work. "I'm a one-play-a-year girl," she says. "I love acting, but it's jolly hard.
"At my age, pulling yourself together at half past five in the evening, going to the theatre, finding a parking space, doing the show, and the late nights - frankly, you're whacked. But I do love working."
So much so that when in 2002 the Daily Mail attacked her as "an embittered woman" who had gone into retirement, she sued the newspaper and won £38,000 damages, which she donated to charity.
As well as work, she also loves life. "I smoke and I'm a great one for a glass of wine.
"I spend the summer in France, cooking, eating, reading, listening to music and wallowing in the pool. And listening to owls at night. Privacy and silence are wonderful things and they lead to something else that is valuable, which is introspection."
Rigg is quite a private figure, although she did talk about her past in a television series, Empire's Children, last year. She was born in Doncaster in 1938, but her parents were based in India.
Her father, Louis Rigg, was a railway engineer who worked for the Maharaja of Bikaner, Ganga Singh. His wife Beryl returned to Britain for the birth of her daughter, then returned to India.
Although Rigg felt a bit guilty about her Empire upbringing during the anti-Establishment 1960s, she is now fiercely proud of her father's contribution to the Raj. "The programme was celebrating the Empire, and about time too.
"My father owed a great deal to the Empire. And so did I. He actually served the Indians and worked for them. He was much liked by his workforce. So the programme was a lovely opportunity to pay homage to him and to the Empire."
The programme also gave Rigg a chance to revisit India. "It was fine, lovely to go back to where we had once lived. Wasn't remotely spooky. The first place we lived in was completely tumbled down.
Extraordinary how small it was. And then the second house was enormous. It was vast. And we had a lot of Indian servants looking after us. And then, of course, we came back to postwar England - miserable, not a banana in sight, let alone a Mars bar."
Rigg was appointed a CBE in 1988 and a dame in 1994 for her many contributions to theatre and film.
Her career enjoyed a late blossoming in the 1990s, after her divorce from man-about-town Archie Stirling, her second husband and the father of her daughter Rachel Stirling, who is also an actress. The marriage broke up in 1990 after Archie Stirling had an affair with actress Joely Richardson.
Nowdays, Rigg's dislikes - rudeness, noise and selfishness - might fool you into thinking that she has become a grumpy old woman, but actually she is determinedly optimistic and cheery.
Of course, she does cast a critical eye over the way we live, and one of her pet hates is narcissism. "The first person singular in conversation crops up a lot. Sometimes when I'm sitting next to somebody really boring at dinner I count the number of times they say 'I' - it's a game," she says with a wicked twinkle. "It gets you through dinner.
"In about five years' time, I shall be carrying a very big brolly and shall be a very cross old bag and hitting people if I don't like the way they treat me," she laughs. Yes, Dame Diana promises to be even more formidable than she already is.