With the help of a mass celebrity following, Sass & Bide launched the trend for skinny jeans and daringly low-cut hipsters.

Sarah-Jane Clarke and Heidi Middleton have a knack of creating what women want even before we realise we want it. In 1999, under the moniker Sass & Bide, the Australian duo produced a line of jeans called East Village. It was a classic hipster design made in stretch denim which was cut so daringly low that the two-inch zip barely covered a girl's modesty. It also happened to spark the fad for low-rise jeans which, for years, signed the death knell on anything that should dare come anywhere near as high as the belly-button. "When we launched the East Village it went absolutely crazy," says Middleton. "There were queues coming out of all the outlets in Sydney and they were selling out before they even hit the stores."

A few years later the duo brought out another design called the Frayed Misfit. This was a very, very tight jean, again made in flattering stretch denim. When Kate Moss got her hands on a pair, she singlehandedly kick-started the skinny-jeans fad which goes on to this day. "We do live and breathe fashion and I like to think we have a good eye, but we have been very lucky with those two products," says Middleton. "We were on the cusp of the next big thing at exactly the right time."

Clarke and Middleton met in Brisbane when the boys they were dating happened to be best friends. They quickly became good friends and decided to take a gap year to London, where they ended up selling vintage clothing and customised jeans on a stall in Portobello Market. They would buy raffia from the VV Rouleaux haberdashery on the King's Road and sew it on to cut-off denims just below the knee. "It sounds terrifying now, but we did get a great response," says Middleton. "We also did lots of eclectic, vintage-inspired stuff theatrical but still sexy." And that was over a decade ago, way before anyone had ever even heard of Sienna Miller or boho chic.

After moving back to Sydney, following the success of the East Village jean, Sass & Bide decided to test the waters on the global market. "I was incredibly hungover from a friend's birthday one day, and with my Dutch courage I decided to cold-call the head buyer at Harvey Nichols. The buyer said, 'I'm in Sydney but getting on a plane in two hours. If you can be here in 20 minutes I'll look at your product.'" Middleton shoved a pair of jeans in her handbag and hopped in a cab. Harvey Nichols ordered on the spot and has been stocking Sass & Bide ever since.

This success gave Sass & Bide a platform to launch a ready-to-wear line, and in 2003 they debuted at London Fashion Week. They now create four collections a year and have a celebrity following that includes Sarah Jessica Parker and Kylie; their Resort line has just gone into stores, while their autumn/winter 2007 sunglasses and underwear range a new area for them is due on these shores in the new year. They are currently scouting for a site in London to open a flagship store.

In many ways the company and the clothes have grown up with the two girls. But that doesn't mean the've turned their back on the younger market, for whom in January they are launching a diffusion line called S&B Vie. "We had teenagers ringing us up, asking why we weren't making things for them," says Clarke. "This company is a bit like a wild monster. What started out as two girls on a stall turned into three and now there are 55 of us."

Business aside, it's been something of a turbulent year for the girls. In February, when she was heavily pregnant with her second child, Middleton was diagnosed with breast cancer. Her baby was induced and, a week after the birth, Middleton had a lumpectomy followed by chemotherapy and six weeks of radiation treatment. "I feel like I've just been spat out the other end," she says. "The prognosis is great, but to me it still feels like I've been given extra time."

Within weeks of Middleton's diagnosis, two of her other close friends were also found to have cancer. One, her 32-year-old friend Kate, didn't make it. "You can't really take that kind of pain away," says Middleton. "It's been a very heavy time."

After six months out, Middleton is now back at the helm and their next collection, Rainbows for Kate, to be launched at New York Fashion Week in February, pays homage to her late friend. "It's going to be a very happy, amazing show that has Kate's spirit woven into every piece," says Middleton. "I only stumbled across my lump by accident, so I do feel ridiculously lucky to still be here. It could have been a very different story."

Sass and Bide (www.sassandbide.com) is available from Selfridges, Harvey Nichols, Harrods and Net-A-Porter

Beauty spot

Got the jeans? Here's the other basics you'll need

By Eliisa Makin

1. All-American smile

Electric toothbrush with UV sanitiser, 179, by Phillips, www.philips.co.uk


2. Hair today...

Travel epilator, 25, by Boots, www.boots.com Silky smooth in feminine pink

3. Have a close look

Magnifying mirror, 20, by Per Una, www.marksandspencer.com

See every pore

4. Go straight

Hair straighteners, 30, by Morphy Richards, www. morphyrichards.co.uk Still the best