She has played everything from a prostitute to a nun, yet Susan Sarandon insists her appeal lies in portraying the lives of ordinary women. Suzie Mackenzie discovers the private side of an outspoken actress who prizes the human touch

Who would have thought it? That one of the most successful screen actors in Hollywood today would be a woman nearing 60. A woman of outspoken left-wing sympathies - at the Oscars in 1993 she drew attention to a group of Haitians interned in Cuba, more than a decade before most of the world had heard of Guantanamo Bay. Who has no problem admitting that she took drugs in her youth: "I came of age at a time when people questioned. And part of that questioning was taking mind-expanding drugs. I took mescaline, sure." Or that she has had an abortion. "My first [and only] marriage was falling apart. I had an affair with an insane guy and I knew having a kid with him wasn't the right thing." And who now chooses to live with her - 12 years younger - partner, actor/director Tim Robbins, and their two children, John Henry and Miles, rather than marry him: "I like getting up knowing I am choosing to be with that person."

Susan Sarandon speaks like this about everything - candid, open, straight at it - fixing you with those famous, screen-filling eyes. When she arrives at the restaurant where we are meeting - black jeans, sneakers, Agnès b leather jacket - I think she looks grumpy. As it turns out, she is only hungry. "Famished." After downing a cappuccino and a roasted calamari salad in five minutes flat, she is fine. "Now I am ready to go."

She doesn't give you showbiz platitudes about her fellow actors. I ask about James Gandolfini, who plays opposite her in her latest film, a madcap musical, Romance & Cigarettes, directed by her friend, the actor John Turturro, a loose autobiography based on his matriarchal family. Gandolfini is the errant husband who falls for a much younger woman, the sumptuously vulgar Kate Winslet. James is great, she says. "He can get away with stuff, God knows, he's like an overgrown eight-year-old."

Her two boys are 13 and 16. "Yeah . . . And I'd like to go on the record here and now and say that I hope they don't grow up to be like James. He's a bad boy. But you forgive him because he's so human." Human is a word she uses a lot.

Sarandon comes from a family of nine children; she is the eldest. Home, New Jersey, was a chaotic throng of humanity, all the kids packed into two rooms on bunk beds. "It was fun, it was crazy."

Every family on the lot had at least seven children, some had 20. "My mum would have had more babies, but some of them died, some were miscarriages." Women were trotting kids out, she says, "like one of those mimeograph machines". Her parents were Catholics, her mother of Italian/Sicilian extraction, her father a Celt: "Irish, Welsh and English".

Philip Tomalin, her father, known as Tommy, was a big-band singer and head of troop entertainment in Italy during the war. "He introduced Burt Lancaster to his wife. And I have photos of him with Marlene Dietrich." An expansive vaudevillian character, he used to sing a lot at home: "I was always told I had a terrible voice. That gave me a phobia right up until The Rocky Horror Show." Tomalin later became a vice-president of the advertising agency Ogilvy & Mather.

Her mother Lenora was brought up in an institution run by nuns, a charity case, abandoned when she was two. Her mother's mother had her when she was 13. "What no one ever mentioned, until much later, was that the father was in his 20s." Sarandon tried to track down this grandmother, Anita Regali. "She ran a jazz club and was Mafia connected. I've seen a picture of her in the newspapers wearing a turban. That's all I know." That, and the fact that when she would try to visit her daughter, the nuns turned her away.

In Dead Man Walking, where Sarandon plays a nun, she threw away every image of every nun she had ever met. "I'd never met one who wasn't a miserable woman. Not one who was life affirmative."

Sarandon's parents separated in 1982, after nearly 40 years of marriage. "Dad retired," she says. "He wanted to go and live in this real cool house I have in Maine. She refused to go and that was it." So that was her mother - a woman who wouldn't be negotiated into something that didn't suit.

The best of Sarandon's films show life as it is. "The women I portray and the woman I am are ordinary," she has said. "I hear my own daughter, who is 21, and she's very clear about her own standards, about what she'll accept and what not. And that's right at her age. But as you get older you change. You accept human weakness. You start to understand what you'll forgive in yourself, and in others, and what not. And that not every mistake means that you have to burn the house down."

THERE'S NOTHING AGGRESSIVELY assertive about her. She can bother you alright, but she bothers you quietly. Viz that scene in Dead Man Walking where she's Sister Helen, paying her first visit to a man on death row. The priest who greets her mistakes her sincerity for his own brand of sanctimony. He thinks she's a do-gooder. She corrects him matter-of-factly. "He wrote to me and asked me to come." Quiet moral conviction is what you get from Sarandon in this film.

What she does best is to play the parts of people who have no part to play - life's losers. But be careful before you pity them, because these losers are way past wanting pity. Nowhere does she do this better than in White Palace (1990) with the incomparable James Spader, both of them meandering through their godforsaken universes - bits of it are as funny as Godot.

I ask what she thinks is her enduring appeal. She doesn't have to think for long. "To certain people, there's an attractiveness in a woman who says, 'I have a secret and I've figured it out . . .' as opposed to a 20-year-old who doesn't have a clue. At least I didn't when I was 20 . . . So, I guess, for those people . . . someone like me appeals."

She was 17, studying at the Catholic University in Washington, when she met her husband, Chris Sarandon, six years older, an actor and a drama graduate student. She married him four years later.

It was Sarandon who took her to a film for which he was also auditioning, Joe. She got the part, he didn't. It wasn't that, she says. "You need one person at 17, and then you make a transition, and I had never been with anyone else." They were together for seven years before she left him in 1970.

It was seven years later that she met Louis Malle in New Orleans, auditioning to play a prostitute in his film Pretty Baby. She was 32, he was 45, the master director making his American debut, and she was still shy, insecure, convinced when he cast her "he had confused me with someone else". They became lovers on the set and she lived with him for three years, mostly in the south of France, helping to bring up his two young children.

Malle was very smart, very charismatic, very different, she says. "The problem is, if you start to sleep with the director while you're making a film, it's very difficult to break that dynamic - that you are there to make his world happen - after the film is over. And if, further down the line, your world starts to intrude, then you are viewed as, 'You're very ambitious, aren't you?'"

It was now 1980, she wanted to do a play in New York, he wanted her to go to Europe with him to edit Atlantic City. "I stayed to do the play, and that was the end of that. Then he married Candice [ Bergen], pretty quickly thereafter, actually." The humour is all in the timing of that carefully poised "actually". Did she suspect they were having an affair? "I never asked. Knowing Louis . . . he was French, right. But I'm not that interested in chronology."

There followed, for the next few years, a spell of wandering in the States and in Europe. She was still acting, "but not getting great parts". In London, filming The Hunger in 1983, a rather horrible film about vampires, she had an internal haemorrhage and was told she would never have children. "They said, 'You have terrible endometriosis, a lot of scar tissue, but as long as you never want to get pregnant, you'll probably be OK.' So I threw away my birth control pills."

Suddenly, acting didn't seem to offer enough any more. "I felt I'd demystified the whole acting thing. I was kind of bored. I'd paid off my debts. I was trying to figure out a direction for my life. I started to get involved politically again."

And then a "miracle" happened. In Rome, where she was playing Mussolini's daughter, she ran into Franco Amurri. She'd known him as a PA on a previous film. "And I remembered him. He's Italian and quite remarkable-looking, beautiful." In a matter of weeks she found out she was pregnant. She describes it as the answer to all her prayers.

"One day, I was feeling overqualified for everything I was doing. And now here was something I couldn't possibly be overqualified for." Their daughter Eva was born in 1985. "I'd live some time in Rome. Or he'd come here. He was in our life and not in our life." It was hard work: "I felt like I was doing too much work to keep that relationship going."

So when, in 1988, she was sent the script of a baseball film called Bull Durham, with a big part for an Emily Dickinson-reading, proto-feminist, baseball groupie - "I think it's the best written script I've ever read" - she decided to go for it. She didn't think she stood a chance. She hadn't been working much and, though there had been The Witches Of Eastwick the previous year, with Cher and Michelle Pfeiffer, that was really a Jack Nicholson solo flight. Bull Durham writer/director Ron Shelton didn't want to see her.

"They had an A list, Meryl Streep and whoever, which I wasn't on." But Streep and whoever wouldn't audition. And Kevin Costner, who was the star, was insistent that the sexual chemistry and tension between the three main leads in the film was so important to its success that both the two other parts had to audition.

One of the actors put forward for the second male lead was the young, relatively unknown Tim Robbins. "They didn't want Tim either. It was Kevin who fought for both Tim and me. Neither of us would have got it if Kevin had been less secure, less generous."

Sarandon flew from Rome to Los Angeles. Costner got his chemistry. "Kevin's a back-foot actor, he makes you come to him. Tim is a front-foot actor - come on guys, follow me." Costner was the consummate romantic lead. Robbins played the arsehole. And, as she says, "No one plays an arsehole as well as Tim. He really set Kevin up." And she got to get both the guys. She didn't get together with Robbins on the set - she had learned that lesson from Malle. "Yes, I fell in love with Tim. But I came out of that film no longer wanting to settle for a compartmentalised life - guy here, career there." It was just over a year later that her first son with Robbins was born. They have been together 18 years.

Relationships are impossible, she says. "Throw children into the mix and they're really impossible." Add to that the nature of a job that means, "sometimes you're both doing a 14-hour day". Or not working. "And nobody feels completely secure all the time." She thinks of them as "survivors". "At some point you have to stop looking at who's coming in through the door and try to make something work. And I happen to think Tim's really remarkable. I respect him, he's smart, he's passionate, he's committed, he has a sense of humour. And he keeps me on my toes. I think that's what we owe to each other."

AS AN ACTOR, she says, you have choices. "You can use your career, or you can let it use you. I have tried, in however small a way, to do the former. Surviving in this business without becoming bitter, or alcoholic, or going crazy, is a challenge. I have always seen it as a tool to serve things that are more interesting to me. I know I'm privileged, I know our children are, too. But I believe that people can make a difference and I've taken advantage of the opportunities I've had hopefully to try to make the world a better place."

Romance & Cigarettes is a story of human frailty - where the wife discovers that her husband has been having an affair when she finds a poem that he has written to his young lover. Later, when he is fatally ill with lung cancer, she takes him back home to nurse him. "It's about the grace of forgiveness," Sarandon says. "What gets to her is not so much the affair but the fact that he's written the poem, and a f***ing bad poem. And that it's such a cliche. That you think you have someone so special and then they fall into that. Of course it's a temptation for an older man with a huge ego and not much confidence to be adored by a younger woman. So she is disappointed."

But she forgives him. "Yes," she says. "Forgiveness is the name we give to love." Would she leave Tim if he had an affair? "No. I say that, but I don't know what I'd do. I'd be disappointed, it would depend on who it is. I'd have to re-examine." Would she have an affair? "I get offers. But when I play through the reality of what that means - of telling the children, of hurting him - the ramifications are enough of a downer to take the excitement of the offer away. "

She has never been a jealous person, she says. "For the most part I give Tim a lot of rope. If he's out till dawn and I know it's an all-nighter, then that's fine. And he's the same with me." Her natural instinct is negotiation, she says. But, a word of warning. Should she ever hold a gun to your head and threaten to fire it, my advice would be to take her seriously. This has happened twice in her movies, as I recall, in The Client and again in Thelma & Louise. In both, the men who called her bluff came off very badly indeed.

Romance & Cigarettes is on general release