In new comedy caper The Love Punch, Emma Thompson and Pierce Brosnan play a former husband and wife who grudgingly join forces to recover their stolen retirement fund.

As their adventure gathers pace, the at-odds pair begin to rediscover the qualities they loved about each other before their marriage crumbled.

Thompson has been happily married to actor Greg Wise since 2003, but the film got her thinking about whether couples should "take a kind of sabbatical" every so often.

"It's actually not a bad idea to say, 'OK, just for a year, you need to go off'," she says.

"Not be with other people - I think that's very difficult, all that free love stuff which has been tried and tested and proven to be very, very tricky.

"But it's interesting that two people who know each other very well come back together again and love each other in a different way, a better way."

Wise needn't start packing his bags just yet, as the frank and forthright star quickly clarifies: "I'm not talking about myself. I'm talking in general about long-term relationships."

Time apart clearly seems to have worked for Thompson and Brosnan's Love Punch characters, Kate and Richard. After heading to France to steal a diamond worth 10million US dollars from the financier who has defrauded them, they end up bonding again over dodgy disguises, boozy dinners and a car chase down an alarmingly steep set of steps in Paris.

Most Oscar-winning actresses would happily pass driving duties to a stunt double, but the decidedly unstarry Thompson insisted on getting behind the wheel.

"I was just having too good a time. Each time we did it, I drove up another of the steps so instead of being three steps up, we'd be four steps up. The angle got more acute, and Pierce's terror became more apparent, which of course made me want to go further," she recalls with relish.

"It made me want to do more of that kind of thing. I really enjoyed the daredevilness of it, and being allowed to do something that's illegal."

Thompson also took control during a kissing scene with former Bond star, Brosnan. "I just messed up in various ways as many times as I possibly could," she jokes. "He said, 'Have I been kissing you all day?' And I said, 'Yeaaahhh'."

The four-time Oscar nominee probably won't be adding a third Academy Award to her trophy cabinet with the light-hearted movie, but you get the feeling she loved every minute of filming, from waddling around in a scuba-diving suit to getting hit over the head during a volleyball match with a gaggle of bikini-clad twentysomethings.

"I am basically a clown," she admits. "If I could wear a red nose all day, every day, I would."

Pratfalls and painful wetsuits aside, Thompson glows throughout the film, and in the flesh, looks younger than her 55 years in a chic black and navy blouse and black wide-legged trousers. Indeed, she was recently unveiled as one of the stars of Marks & Spencer's latest advertising campaign, modelling alongside singers Annie Lennox and Rita Ora.

But aside from her bleached blonde locks ("I dye it because my hair is the colour of dead mice," she says), the actress is all natural, and fervently so.

Bring up the subject of Hollywood's fondness for facial nips and tucks, and her voice rises considerably.

"It is absolutely psychotic to shoot Botox injections into your face. It's mad. It's not a normal thing to do, and the culture that we've created that says it's normal, is not normal," she says, her frustration evident.

"Why do people ask persons to cut them open and put things into their body? What is that, what are we doing to ourselves? It's chronically unhealthy and there's this very serious side to all of that because we're going to end up with this sort of 'super-culture' that's going to suggest to young people, girls and boys, that this looks normal. And it's not normal."

Thompson softens when talk moves to Gaia, her 14-year-old daughter with Wise. In 2003, the pair also 'informally adopted' Tindy, a 16-year-old Rwandan former boy soldier.

Unlike Kate's daughter, who gets a tearful send-off as she departs for university in the film, Gaia won't be fleeing the nest just yet.

"Mine is 14, so she's doing that thing of going out of the nest and then coming back, but not going too far," says Thompson.

"You identify with your children in a way, I suppose that's a healthy thing, but then in the end you have to say, 'That person has their own life'.

"You've got to be there to be picked up and used as and when you're needed, and of course you've got to be there for support, but you can't interfere too much. Learning to step back, that's the art, isn't it, of being a parent?"

Gaia is keen to support her mother too, larking around with her at the Baftas and looking on as Thompson kicked off her heels and sipped a Martini on stage at the Golden Globes.

"I didn't go away very much when Gaia was little, but if you ever do have to go away, then now she says, 'No mum, I think you should do that', and we can discuss it," she adds.

"They're very proud of what you do - as long as you're not away all the time, that would be bad. But it's really interesting how [children] change. They're very good at keeping us steady."

Our time is up - though Thompson admits she could "riff on about motherhood for days".

It's clear that, for all the plaudits and plum jobs, being a mum is the role she prizes most.

EXTRA TIME - EMMA THOMPSON

:: Emma Thompson was born on April 15, 1959, in London and grew up in West Hampstead, the daughter of The Magic Roundabout narrator Eric Thompson and actress Phyllida Law.

:: She studied English at Newnham College, Cambridge, where she joined the Footlights theatre group, making appearances with fellow alumni Hugh Laurie and Stephen Fry.

:: She married actor Kenneth Branagh in 1989. They starred alongside each other in films including Peter's Friends and Much Ado About Nothing and were married for six years.

:: Thompson won the best actress Oscar for 1992's Merchant Ivory adaptation of Howards End. She picked up another Oscar for her 1995 screenplay adaptation of Sense And Sensibility.

:: She met Wise when he played dashing John Willoughby on the set of Sense And Sensibility. She has said of her husband: "He's the only luxury I really can't imagine ever being able to give up."

:: The Love Punch is released on Friday, April 18