Up close with Hollywood's golden girl

Reese Witherspoon looks visibly relieved to be discussing the perils of the dating game from the safe vantage point of her new-found happy marriage.

Maybe it's because she's been a mother for most of her adult life – she was just 23 when she had her first child – or perhaps it's because she married young, but the actress was curious to know how it felt to be a single woman with two men fighting for her love.

"It's every woman's fantasy to have two unbelievably hot, sexy guys battling over you," she teases today. "I'm doing this for the ladies."

The result is the action comedy This Means War, featuring Tom Hardy and Chris Pine as CIA agents fighting it out for her affections.

Now that she's tried on the dating game for size, if only on screen, Witherspoon can't help but glance down contentedly at her wedding ring as we debate the changing face of sexual politics and internet dating.

"I just find dating nerve-wracking, and really, I don't date. I went from being married and then I was married again, so I didn't really date much," says the actress, who was wed for eight years to Ryan Phillippe, with whom she has two children; their marriage ended in divorce in 2007. She went on to date Jake Gyllenhaal for two years, before finding lasting love again with agent Jim Toth. The couple married a year ago in a ceremony at her ranch in Ojai, California.

In This Means War, her character's best friend urges her to choose between suitors by having sex with them. But in real life, Witherspoon takes the higher moral ground. "Sexual politics are always changing; that's life and you kind of have to go with the flow – but no, I never dated two people at the same time. I wouldn't know how to keep up with two – I can barely keep up with one! Is it OK for a woman to do that? I have no judgment on people who decide to do that, as long as they are honest.

"Relationships aren't always easy, and I think you have to be ready for a relationship. You can't do the right thing with the wrong person; you can't do the wrong thing with the right person, so once you're finally in the right situation, I think you have to be willing to compromise and negotiate and all that kind of stuff."

One of the most diverse actresses of her generation, she slips easily between comedy, romance, period fare and drama. And while she took home the Best Actress Oscar in 2006 for her portrayal of June Carter in the biopic Walk the Line, she's often better recognised for her fine-tuned comedic skills; her This Means War co-star Tom Hardy described working with her as a "master class in the comedy genre".

At 35, and still at the peak of her beauty, she is cognisant of the declining screen value for ageing actresses, saying sagely, "I think it's hard to imagine being in your early 30s and your career being over. So, certainly, as an actress, I think about longevity. I mean, that's more for us women than for our male counterparts. I hope to have as long-lasting a career [as the men]."

Witherspoon has recently completed work on the Mississippi drama Mud; she'll also portray 1950s artist Margaret Keane in Bug Eyes, and she's co-starring with Colin Firth in next year's satanic thriller Devil's Knot.

"I have a production company, but I don't personally make a lot of movies," says the actress, who presides over the flourishing Type A Films, which she set up after getting a taste for the business side of film-making after executive producing Legally Blonde 2 in 2003. "I personally usually make one movie a year, because I have another full time job, which is being a mother."

Witherspoon has long refused to be a victim of her own celebrity, to which end paparazzi frequently snap her going about her normal day, be it jogging in the park or collecting her children Ava, 12, and Deacon, eight, from school.

Born in New Orleans to Catholic parents, she was raised with a typical Southern gentility which often makes her stand out from the brasher elements of Hollywood.

Throughout all her film success, achieving box-office highs with Cruel Intentions, Legally Blonde and Sweet Home Alabama, she has remained close to her family, to this day never forgetting to credit her mother for guiding her through life.

If her This Means War character is forced to choose between Chris Pine and Tom Hardy, then Witherspoon herself refuses to choose between her co-stars. "I'm married and my husband probably wouldn't be happy with me choosing either one of them."

This Means War opens on 2 March