You have to hand it to them: trashy teenage Australian soaps have proved a fair dinkum hit when it comes to launching the careers of their young stars. Without Neighbours we wouldn’t have Kylie Minogue, Guy Pearce, Russell Crowe or Natalie Imbruglia. And without Ramsay Street’s great rival Home and Away we wouldn’t have, er, Isla Fisher.

The actress, who played the young tearaway Shannon Reed, featured in some of Summer Bay’s steamiest storylines that put Kylie’s wholesome trysts with Jason Donovan in the shade. From 1994-1997 she was forced to endure half a dozen tearful relationships, suppressed memories of child abuse and anorexia before finally running away to France with her lesbian lover. And all this before 6 o’clock on a weekday.

In real life Fisher, 31, is now one half of one of the most unlikely relationships in showbiz. For the past five years she has been engaged to Sacha Baron Cohen, star of the Ali G show, now better known as Borat the Kazakh journalist, with whom she is expecting a baby in October.

She accepts that at first glance the pair make an eccentric couple (for a start she is 5ft 3in, he is 6ft 3in), but claims that this is nothing new to her. “I’ve always been strange. My mum used to call me eccentric when I was like three – my ears were this size when I was just two years old!” she says, flicking back hair to reveal a large pair of ears. “I’ve always been different. What can I say?

“I’ve always been drawn to the absurdity of life. In this respect, Sacha and I are very similar. We hide our true feelings behind humour.”

Since Baron Cohen’s huge success as Borat in America the pair have been firmly thrust into the limelight. “I really enjoyed not being noticed, but we’re starting to have our pictures taken a little more often now,” she says. “I think it’s because Sacha’s so tall while I’m so small I’m like a circus freak.”

The fact that they have moved to Los Angeles means that they now count celebrities such as Naomi Watts, Jennifer Aniston and Courteney Cox as their friends. Fisher has also taken to driving a fashionable eco-friendly car. “I’d wanted to get a hybrid for a while,” she says. “I had my name on a list. So now I drive the new Nissan Altima Hybrid.

“I used to drive a Mini Cooper. I loved my little car but, unfortunately, my belly no longer fits under the steering wheel. It really wasn’t easy, not to mention the suspension on the Mini Cooper. It’s like a little racing car with a BMW engine. But I am still a good driver. I always was, even in my first ever car, a Datsun Bluebird.”

An LA address, celebrity friends and hybrid cars? It’s all very Hollywood and a long way from Summer Bay. You can take the girl out of Australia but not Australia out of the girl and Fisher is nothing if not a typical Aussie battler.

Born in Muscat, Oman, to Scottish parents, Fisher was taken to Perth, Australia, when she was still a baby. By nine she was making appearances in television adverts, and after her stint on Home and Away she moved to London. There she followed the well worn route to semi-stardom: provocative shoots for lads’ mags, top 10 appearances in world’s sexiest women polls, flings with Coronation Street actors, and a couple of small TV roles. It was during one such stint that she met Sacha Baron Cohen, then starring as Ali G.

In 2001 she was cast as Mary Jane, Shaggy’s love interest, in the film version of Scooby-Doo and followed it up playing a sex-obsessed bridesmaid in the hit comedy Wedding Crashers.

Her own wedding will be more refined, she says: “We’re definitely going to have a beautiful traditional Jewish wedding. I’d do anything to ensure our future together as man and wife. To that end I’ve been learning about Judaism, which I find very beautiful. Its enriched my life enormously. I love religions and find them fascinating.”

She won’t be the first actress to convert to Judaism in the name of love. Kate Capshaw, Marilyn Monroe and Liz Taylor did likewise upon marrying Steven Spielberg, Arthur Miller and Eddie Fisher respectively.

Her latest film sees Fisher starring alongside Ian McShane and Sissy Spacek in Hot Rod, a film about a wannabe Evel Knievel who sets out to jump over 15 buses to raise money for his stepfather’s heart surgery.

The film is one long cavalcade of stunts, pratfalls and injuries but Fisher was left on the sidelines. “They wouldn’t even let me perform a single stunt,” she says. There was one stunt where all I had to do was stand on the back of a moped. I wanted to do that stunt myself because, basically, nothing much really scares me.

“I was a daredevil as a kid and loved to skateboard. I never remember my knees or shins or elbows without scabs on them. I have two brothers and two stepbrothers so I was a real tomboy, leading a pretty outdoorsy lifestyle. I rode horses for years and used to do cross-country one-day and three-day eventing.

“I would have liked to do more action scenes in Hot Rod but I can’t really complain. They say that giving birth is the biggest stunt of all.”

So will she be collaborating on any film projects with her other half? “God, no! I mean, how successful are married working relationships? Nicole and Tom split up after Eyes Wide Shut; Sandra Oh and her husband Alexander Payne, [the film’s director] separated after Sideways. I feel like working together is the kiss of death.”

On her CD changer

The Kinks and rapper Nick Cannon, although I’m not really in the mood for rap right now. Having just got back from Bora Bora, I’m into French Polynesian music too