'Shine a light on an oil painting from the front," says Jacqueline Bisset, "and it looks wonderful. Shine a light on it from the side and it looks really craggy and peculiar. That's the way I feel about my face now. It is craggy, and I'm both proud of that and scared by it." In Catherine Hardwicke's Miss You Already - which she is in London to film opposite Drew Barrymore and Toni Collette, Bisset suspects she will look "pretty rough".
"As an actress you can try and hang on to your image by being lit very carefully - and end up looking amazingly young. But obviously I'm never going to ask for that. In life," she shrugs, giving her famous mane a shake, "I suppose I'm afraid of being discounted. And there are times now when I feel completely invisible in the street."
The Surrey-born star isn't prone to such frivolous introspection. It's at my insistence that we find ourselves immersed in the subject of ageing - because after 50 years on screen, Bisset turned 70 this month. "Although I'm grateful to have reached this age," she goes on, still unnervingly beautiful, "crags" and all, "because my father died at 70 and I lost many of my dear friends in their sixties, I can't say it has been terribly amusing to see everything change. Still I don't agonise about it."
Bisset earned her stripes in the late Sixties and Seventies opposite the likes of Steve McQueen in Bullitt, Frank Sinatra in The Detective, Christopher Plummer in The Spiral Staircase and Marcello Mastroianni in The Sunday Woman. Her views are of the well-formulated, non-stock kind and, although she keeps trying to reign us both back to the film she is currently promoting - the brilliant Welcome to New York, directed by Abel Ferrara, in which she plays Gerard Depardieu's beleaguered wife - she seems to be enjoying our wild tangents as much as I am.
"Women are becoming so tough," she says. "I have never fully embraced feminism. I certainly thought it had some good points, but…" But women whinge too much nowadays? "Well I don't know, but I think they probably do. Then again, women take on too much so of course they whinge, because they're absolutely exhausted. That's our mistake, always wanting to be perfect."
When Bisset first moved to Hollywood in her early twenties - where she enjoyed lengthy romances with actor Michael Sarrazin, the Russian dancer Alexander Godunov and martial arts instructor Emin Boztepe but never married - she "wore herself out trying to be perfect", she says.
"When I met the first man I had a real relationship with, other women would ask: 'Why do you do everything for him when you're not married?' When I explained that I liked to take care of him, they would say: 'Marry someone rich, then you won't have to do that.' What a peculiar idea! Never for one second was that my goal. But maybe that's because I'm a rebellious type."
That rebelliousness may have been a compensatory response to the acute self-consciousness she suffered as a child. The daughter of a Scottish GP and his French wife, Arlette, Bisset grew up in Reading. When her mother developed multiple sclerosis during her teenage years and her father left, she took up modelling to support them both.
"I never felt beautiful. That just wasn't the way I was brought up. I was always more interested in men than my own looks," she says. "I liked men. I liked them in a very wholehearted way, and I didn't feel that my looks were what they found most attractive in me. Yes, some of them wanted to jump my bones but I never understood that whole 'sex is all men want' thing. That's such a narrow point of view - and not true at all.
"Girls today are so attractive and sexy, and they show themselves off in such an obvious way, so men feel that they are in a sweet shop. The flip side of that is that women see themselves as interchangeable. I feel that this obsession to be 'hot' is more prevalent than it ever was in my youth. It's not 'I want to be charming and magical and romantic and beautiful'. It's 'I want to be hot'. In other words: 'I want men to want to screw me.' "
What does she think that's about? "Desperation, isn't it?" she says wearily. "Because they don't really want to deal with the results and often end up feeling used. I went through a period like that. When I dressed and behaved in a certain way, I couldn't handle the results: it didn't take me where I wanted to be. So I started to be more low-key and I got better relationships as a consequence."
Today, Bisset's professional choices are largely dictated by how much of a personal life she wants. "These days I want to enjoy the kind of career where I can still have a conversation and not be interrupted, because I know what that is. I've been through that."
Bisset has never written an autobiography. But judging by the look on her face when I bring this up, that's one book that will never be written. My emotional life has been the most interesting part of my life but I don't want to write about it. It's been rich and difficult but it's nobody's business. Also," she adds with the smallest of winks, "it's still ongoing."
'Welcome to New York' is in cinemas now and released on DVD on October 20