Diana Rigg says that the best part of being a mother is that it's the sexiest feeling in the world. The other day she startled her paediatrician by declaring she was passionately in love with her baby daughter, Rachael, and should she be worried by this?
"It's positively dangerous when she's laying naked on the bed," she says self-mockingly. "I sink my teeth into her flesh. I bury my nose in her stomach.
"It's purely sexual. Well, love and sex. The sexy part is the other person. She has her father's skin. So I said to my paediatrician: 'Should I be guilty?' and he said: 'Absolutely not. Show her how beautiful you think she is. Be free to do absolutely what you want with her.' And I do.
"She responds to this like Goya's naked Majha. She lays back and accepts all the homage I give her."
Diana Rigg always used to be the feminists' quintessential symbol of independent woman. Men were to appease an appetite, feed the vanity. Domesticity was a drudge.
Diana was portrayed as the self-sufficient loner. A potent cocktail of shimmering sexual attraction and cerebral power.
It frightened and fascinated. She drove open-top continental sports cars and starred in James Bond movies as well as on Broadway.
She lived in a big house by the Thames, which was glossily furnished like the pages of Homes and Gardens, and rich men wanted to marry her. The whole world, it seemed, loved Diana Rigg.
Nobody knew about the nights she left a dressing-room full of people to drive alone from the theatre to an empty house, her mascara smudged with tears, her consciousness asking why, when she had so much, did she feel such despair?
"I remember one night, after appearing in Phaedra at the Old Vic," she says. "It was half past two in the morning. I'd taken my make-up off but not fully, so the face was a bit streaked. I was sitting at the traffic lights on Vauxhall Bridge waiting for the lights to turn red.
"There I was. Slumped over the wheel like death. Desperate and sad. And a little man in a van drove up. He motioned to me to wind my window down and when I did he said 'did you know you are beautiful'. It was so touching."
Today Diana Rigg's sad secrecy has been replaced with the kind of happiness for which she says she is "pathetically grateful!"
She has a beautiful 18-month-old child, a strong, stable relationship with former Scots Guard office Archie Stirling, a widely acclaimed hit play in the West End, Night and Day, which has won her the notices of her life, and all in the year that she celebrates her 40th birthday and 21 years as an actress.
"I am incredibly happy," she says. "I still feel grateful to Archie that I am able to say 'I need you.' Archie has given me trust. He pointed out to me the fallacy of my independence. It took an enormous and quite painful jump for me to say 'I am dependent.' It absolutely stuck in my throat but it had to be said.
"Coming from a very different world he held a mirror up to mine and showed me quite a lot of aspects of it which weren't attractive. He made me take a very harsh look at myself.
"I have gone through periods of my life when I have been desperately unhappy. Periods when I was incredibly successful professionally but really very lonely.
"An independent woman has always been portrayed as a very strong woman. I know the fallacy of this. You have to be very strong to say 'I need you.'
"Rachael has made all the difference to my life.
"Of course, I'm absolutely frightened stiff of all the implications of motherhood, though... you know, genetically what's in the poor creature. You very much watch for certain qualities in yourself which you hope she hasn't inherited.
"But Rachael is already very independent. She doesn't hang on to my skirts. She walks around and comes back to me but she doesn't cling to me.
"I like that. I don't want the ego trip of having a baby that only wants Mummy. I didn't reach a personality for a very long time and I want her to find herself as quickly as she can because I think it's the answer to life.
"No, I never miss her bedtime even though I have to be at the theatre at night. It's at 6.30 on the dot. Nothing must interfere with this.
"Motherhood changes you. I used to just pick up and go. Now I have to think... 'do I have enough disposable nappies?'"
I watch Diana playing with Rachael. She puts her daughter on her shoulders and holds her upside down as mother and child pose for pictures to the beat of Elton John records.
It is both an enchanting and natural vision.
Rachael is clearly a born performer. And parenthood has obviously softened Diana, adding a gentler element to her beauty. She is no longer afraid to show her vulnerability. The brittleness has gone.
Diana pours the ice-cold champagne. She is wearing plum-coloured culottes, a pink blouse and cavalierly smokes a man's cigar.
Ms Rigg pushes a hand through her light brown hair, now cut to the nape. The flowing tresses that were always being tossed back so aggressively in all those Avengers episodes were cut for her part in Night and Day.
She plays the sexually hungry, emotionally insecure wife of an English industrialist in an African State, which is suddenly descended upon by a Fleet Street contingent reporting a political emergency.
Bernard Levin described her performance as "like a force of nature". Newsweek said: "Beauty, wit, bitchery and vulnerability seem to whirl about her like a pride of playfully savage ocelots."
She has been asked to take the play to Broadway. And today it won her the best actress of the year award from the critics.
Ms Rigg's projection of hidden vulnerability and devastating attack, both towards the Press and men, is so convincing it has clearly been shaped by personal experience. It is a performance, she agrees, fashioned from the pain and joy of recent events in her life.
In the past few years, following the break-up and divorce from her husband, Israeli artist Manachem Gueffen, she has received much scrutiny from the gossip columnists. She and Manachem were together just a year. Why did she marry?
"It was a grotesque error," she says. "Menachem was a kind of macho toy. I'd never given in to that kind of temptation before."
I mentioned that when I had asked her shortly after the wedding why she had married, she replied, "Well, look at him," as if his physical beauty was the prime motivation. She displayed Menachem with a pride that a successful man might show off an attractive young bride. Diana nods.
"That's exactly right and while it was deeply shaming, I never thought I would make that mistake ever and when I did and it broke up I was a wreck. Why one's friends didn't say: 'Look Diana, see it through as an affair but don't do anything else' I don't know.
"But Menachem was into marriages. I was his fourth wife. I blamed myself monumentally. It damaged my self-respect. It made me dead against ever getting married again.
"I completely withdrew. I went to Mexico. I became a scarecrow. I was incredibly thin. I had all sorts of psycho-somatic illnesses and I punished myself. What I had seen in myself I didn't like.
"After that I was in enormous danger of becoming a fag hag. I was listed in After Dark (an American magazine for homosexuals) as Number Four Fag Hag. A fag hag is a woman who demands nothing of men sexually.
"Top was Liza Minnelli. Second Bette Midler. I came after Ann-Margret.
"In itself it's no bad thing. What it represents is a bad thing. It means you're copping out by living a rather superficial existence surrounded by men who find you pretty and attractive but don't confront you as a woman at all.
"I'm 40 now and I'm fully aware of the physical changes that are taking place. I know the lines that have appeared on my face. God knows, as an actress you have to look at it making up in the mirror every night. I've got lots of white hairs on my head.
"It doesn't matter. I am so happy I thank God every day for what I have."
In the next few months, A Little Night Music, the film Diana made with Elizabeth Taylor, will be released in Britain.
Diana says: "First of all, Elizabeth Taylor is extremely beautiful. Secondly, she is congentially late. And sitting in the studio in a very tight corset with an enormous hat perched on your head burning itself into you doesn't make her incredibly popular in my book.
"I got very ratty I'm afraid. I was sitting there on the set hour after hour and nobody would get her down. I think if anybody had the courage to say 'be here on time' she would respect them and do it."
To friends Diana is incredibly loyal. She still regularly sees old chums from boarding school in Doncaster and put an advertisement in the paper when she lost contact with them.
She says she hasn't decided whether she will go to Broadway. If she does she will take Rachael with her.
The last time she worked in America was for CBS television on a situation comedy about a single girl, strongly modelled on the Mary Tyler Moore show. She had to learn 60 pages of dialogue every five days and was relieved when the series bombed.
"It was written by three misogynists who were tiny and intimidated by a tall woman," she says. "I remember when I started they sent a limousine three blocks long to collect me. When I finished I was taken away by the studio station wagon.
"I laughed all the way to the airport."