Girl meets boy. Boy cheats on girl. Girl hatches plan. Girl gets revenge. It's a Hollywood cliché, to be sure, and one that Cameron Diaz is a little tired of. Not the romance. She loves that. And not the cheating. That's inevitable, she says. "Everybody in the world has been cheated on; there is not one person who has gone unscathed," she declares. Not even the plan bothers her. Girls are, after all, very clever.

It's the revenge bit that seems to stick in her craw. Specifically, the notion that women, particularly in film, are so driven by such a potent, negative emotion, as though it's an inescapable part of their DNA, especially where other women are concerned. Hell hath no fury, and all that. And Hollywood clearly has an appetite for it, from the female buddy flicks Thelma & Louise, Nine to Five and The First Wives Club, all the way to Lars von Trier's Medea and the harrowing Fatal Attraction.

In Diaz's new film, The Other Woman, revenge seems a perfectly justifiable main course, served cold, with a side of I-told-you-so. Diaz plays Carly, a woman who discovers her boyfriend is a married man and that, without even knowing, she has become "the other woman". By chance she meets his wife, Kate (Leslie Mann), and the two women, realising they have much in common, become friends. When a second mistress, Amber (Kate Upton), surfaces, the three women resolve to teach the man who has deceived all of them a lesson he will not forget.

But The Other Woman isn't really a story of revenge, considers Diaz, easing onto a sofa in a suite in the fashionably chic Four Seasons Hotel in LA's Beverly Hills. "It's a film about a relationship between three women," she says. "[Revenge is] honestly not the focus of the movie. It's a part of the movie, but the movie itself, I felt when we were making it, is really about these unlikely friendships."

As for revenge itself? "It's a waste of energy and time," Diaz says, matter-of-factly. "It's one of those things that society gets caught up with. It's instant gratification. We're addicted to that, but it's a waste. When you get cheated on, you have to move past it."

Cameron Michelle Diaz was born in the sun-drenched Californian beach community of San Diego and, as an actor, seems to exude all of that summery simplicity: blonde hair, white teeth, flawless skin. Even at 41 she seems barely out of her 20s, though she rages against Hollywood's well-established fear of ageing, particularly when it comes to women. ("We don't honour the journey and who we are and how much we have to offer," she told Oprah Winfrey recently.)

Her family moved to Long Beach, Los Angeles, when she was a teenager, and she emerged as a fashion model thanks to an intriguing mixture of blonde hair and Cuban heritage. She was represented by the New York company Elite, the same super-agency that has showcased some of the world's most successful models, including Cindy Crawford, Gisele Bündchen and Heidi Klum.

At the tender age of 21, with no acting experience, she was cast opposite Jim Carrey in The Mask. The film grossed more than $US350 million, and Diaz's star was fired skyward. Since then, her story has been writ large from the book of Hollywood fairy tales, albeit one with a body of work that hints at a far broader range than your average cinema blonde – the campy, wry Charlie's Angels (2000), the gorgeous and emotional Shrek (2001) and Martin Scorsese's 2002 historical masterpiece Gangs of New York are just three of the highlights.

Actors, she agrees, are natural chameleons. But she concedes she puts a lot of herself into every performance. Which raises the question: if we have only ever known Cameron Diaz on the silver screen – as "Angel" Natalie Cook, Shrek's Princess Fiona or Jenny Everdeane from Gangs of New York – how much of the real Cameron Diaz have we actually seen? And is The Other Woman's Carly, a seemingly perfect California girl herself, more revealing than her predecessors?

"You could probably see parts of me in [all of those films]. But it's like anything, any character, any part that I play – you're seeing my understanding, my ability, whether limited or broad, of what that character is going through emotionally, psychologically," Diaz says. "Over the years, with life, experience and lessons that we learn, I am certain that if I got to do any of those performances over, I would do them completely differently."

The net result of those performances is that Diaz is one of the most successful film actresses in the world. In 2003, Charlie's Angels: Full Throttle helped push her through the $US20 million-per-picture barrier that only a handful of other actresses – think Julia Roberts and Sandra Bullock – have smashed. When Diaz is not working as an actress, she works with Iraq and Afghanistan veterans, supports environmental causes (such as endangered wildlife and clean energy), and is an advocate for community volunteering.

Actor. Eco-warrior. Activist. It's an impressive list. She's just not sure she's a feminist. "I am not great with labels. I am not a person who likes to put labels on anyone," she says. "But in terms of what you can have and what you can't have, it's all relative. So, what are we fighting for? What do we want more of? If we are fighting to have what men have, is that really what we want?"

Let's start with the basics. "There are certain things we should all have: male, female, straight, gay, whatever ethnicity. Basic civil rights we should all have, absolutely. And we should never stop fighting for that," she says. "But representation in film? [That's] not life or death. We can still live those stories, we can still keep building our own understanding of women and our relationships, and can still, in life, be engaged by those things and not see it on the screen for it to proliferate.

"There are certain things I'd concentrate on, as a human being, rather than a feminist. As a woman, I am not looking to have all the things men have. As human beings, we should all have what we all deserve. I will always fight for that. But whether I feel women are under-represented ... I feel there are a lot of ways I can spread that message, and a lot of ways I can be engaged to help people understand that it's something I think is important."

So, not a feminist, perhaps, but a great and passionate believer in the sisterhood. The Other Woman may be the latest in a long line of girl power movies, but it seems to echo most loudly with 1980's Nine to Five and 1996's The First Wives Club.

At the mention of Nine to Five, one of the most successful films in Hollywood history, Diaz's eyes dazzle. "Yes! I love it," she enthuses. Nine to Five's revenge story (on the "sexist, egotistical, lying, hypocritical bigot" boss) was central. But the enduring appeal of the film is the unlikely friendship of a working mother, an awkward divorcee, and a big-busted country girl, and Lily Tomlin's, Jane Fonda's and Dolly Parton's luminous portrayals of the three as each discovers there is more to the other two than meets the eye.

"Women are taught that we're supposed to be pitted against one another," says Diaz. "I never grew up that way. I was not drawn to women who were competitive with me. Any time I did, I found myself broken-hearted. [So] I just decided that as soon as I felt that from another woman, I'd go the opposite way.

"We live in a society where women are self-sufficient, they can take care of themselves, and what they need are more women in their lives. We understand each other, we know each other, we can be compassionate towards one another, the same way guys are 'bros' and 'buddies' together."

Those male relationships, Diaz notes, are celebrated culturally in the form of "buddy movies", the notion of gladiators, even the public-relations narrative of the armed forces. "With women, that is lacking," she says. We don't get to see how women can support one another and be there for one another." Yet Hollywood has an uneasy relationship with big chick flicks. Despite years of pressure for sequels to Nine to Five, Thelma & Louise and First Wives Club, nothing has come of it.

Diaz is matter-of-fact about Hollywood's appetite for female stories. "With everything, it comes as it's desired. We're seeing a new generation of women who are comfortable with asking for what they want, and the more women ask for that, and [the more] they know what they want, they will start to get it. It's also showing them things: 'Look at this'; 'This can be me'; 'I want to see more of that'. I completely relate to that. It's just a matter of presenting it to them and letting them know they can have it."

For Diaz, "having it all" seems relatively effortless, though she has to do so under the microscope of a modern media that now includes paparazzi and a billion-dollar online celebrity gossip industry. She is extremely guarded about her private life, but has been in high-profile relationships with Justin Timberlake, Alex Rodriguez and Jared Leto. Professionally speaking, The Other Woman is her 40th film in 20 years, with two more due out this year – the comedy Sex Tape, in which she co-stars with Jack Black and Jason Segel, and the film adaptation of the musical Annie, in which she plays the cruel Miss Hannigan.

Having a real life in the slightly unreal fishbowl of fame is not difficult, she says. "It's all about who you bring into your life. There's plenty of [false affection] out there. And I could be engaged with that if I wanted to. But I am just not drawn to that, I am drawn to authenticity and real people. I can sniff fakers out real quick and I have always been able to do that. In the past, whether or not they stayed in my life because I allowed them to, or for my own purposes, is one thing or another, but at this point in my life I am not interested in that and it's not something I have to worry about."

It's also a life lived in the space between the private and the public. Neither world, she says, is a happier space than the other. "Every film I have done, the process of doing it, from beginning to end, is unique, and that's what I love about the job that I do," she says. "So it's not about me, per se. I just try to be as engaged in the moment I am in."

The Other Woman is released on April 17.

Lead-in image: Mario Testino/Art Partner/Raven & Snow.