THE crossover between interior design and fashion has long been acknowledged. Take the big autumn-winter looks from Milan and Paris last year - clashing patterns at Etro, sculptural design at Alexander McQueen, futuristic at Balenciaga and geometric at Missoni - trends that soon appeared in the showrooms of leading interior design firms such as Habitat, Roche Bobois Paris, Baccarat crystal and Ikea.

In the same way, fashion designers are also influenced by interiors. Prada's spring-summer 2002 collection was inspired by the antique damask and lace used in soft furnishings that Miuccia Prada discovered in a Paris market.

For many, the way we dress ourselves and our homes is intrinsic to our sense of who we are. Both are expressions of our personality and how we like to appear to the world. Leading designers in the modern fashion world - Pucci, Giorgio Armani, Ralph Lauren, Missoni, Versace, Calvin Klein, Donna Karan - have been quick to recognise this and have developed multimillion-dollar interior design businesses that go beyond towels, cashmere throws and teacups.

Rosita Missoni made the crossover from fashion to interiors when she handed the reins of her fashion empire over to her daughter Angela in 2001. She was supposed to retire but lasted only a short while. "I tried for a while to play the Italian grandmother - taking the grandchildren to school. But I thought, 'Oh no, this is not the life for me,"' says Missoni, 76, who was in Sydney earlier this month to promote Missoni Home.

"When I left the world of fashion I did feel that the home was becoming fashion. We did already have a collection for the home, which we had been doing with my brother Alberto since the 1980s. It was a good collection and very commercial but I felt it had to become fashion. It was nice quality and good product but there was not a complete style. I didn't feel like having it in my own home."

Italian fashion house Pucci was one of the first to enter the market, with Emilio Pucci licensing his fabrics to upholstery and accessory firms in 1972. More recently French designer Patrick Norguet upholstered a sofa in one of Pucci's archive prints - which was also used by Pucci creative director Matthew Williamson on the Milan catwalk for spring-summer 2007.

Ralph Lauren launched his home range in 1983 and Giorgio Armani has long understood the importance of a complete lifestyle look. The Armani Casa range - furniture, tableware, linen and rugs - and the fashion collection share the same aesthetic. The designer took his business one step further when he opened the first stand-alone Armani Casa store in London in 2005, with personalised interior decor and made-to-measure services for customers who want the whole Armani minimalist monochromatic look. Armani himself lives and breathes his own fashion ideal, with his custom-built 45-metre yacht Mariu decked out in Armani Casa's couches, coffee tables, lamps, desks, beach towels and linen.

In recent years top rug companies have teamed with fashion designers to release special edition designs, the theory being that fashion moves quickly but rugs last. The Rug Company set up business in Britain in 1997 and has collaborated with Matthew Williamson, Diane von Furstenberg, Marni's Consuela Castiglioni and Vivienne Westwood. In Australia, Akira Isogawa collaborates with Designer Rugs.

Leading homewares brands such as Waterford Wedgwood have followed the trend with exclusive designs by Vera Wang and Marc Jacobs, while Matthew Williamson and Roland Mouret have created wallpaper for Habitat.

The conventional view is that designing for interiors is somehow less subject to the whims of fashionability than for clothes and that interior trends evolve more gradually. "I think most creative industries run in parallel to each other and fashion and interiors are no exception," British fashion and furniture designer Paul Smith writes in Marnie Fogg's book Couture Interiors: Living With Fashion (www.laurenceking.co.uk).

"If you look at the mid-1980s, fashion was very minimal - black suits, white shirts - and so were interiors. In fact this style of interior has lasted a long time but slowly, like fashion, interiors are now more about a mix of pattern and colour."

Missoni says her home collection sometimes reflects her daughter's fashion designs but is also created with an eye to longevity.

"The advantage and difference with home furnishings is that you design and make it thinking it is going to stay in your home for a long time. It doesn't go out of fashion. We do one collection a year. In fashion we make four collections a year, for men and women, which is a nightmare. But if I see a lovely pattern in Angela's collection, I will ask if I can use it for my collection. I absolutely do."

Louise Chidgey is a senior interiors specialist at the influential London trend forecaster WGSN. She doesn't believe fashion designers have changed the way we dress our homes nor are they the innovators in the interior design category but she does agree that fashion interiors are big business.

"Innovation actually comes from the real designers such as Patricia Urquiola, who are not in the fashion world. Armani Casa definitely is not an innovator - it is very bland. Missoni, yes. Their use of colour and pattern is outstanding," Chidgey says.

"It is also an exclusive market but those who are the design leaders are Missoni, The Rug Company, Etro, Cacharel and Nicole Farhi. They are all very different in their look but keep loyal to their brand."

According to Chidgey, fashion couches and rugs may be appealing and look great in your home but in the long term, in her opinion, they are not true investment pieces.

Iconic fashion looks can hit the auction houses, which is the case now with vintage YSL, but their prices usually reflect what its owner would have originally paid. However, vintage and antique furniture, in common with works of art, can reach mind-boggling prices compared with the original cost.

"Interiors by fashion designers are not classic in design compared to, say, the Scandinavians, who produce classic and timeless furniture and interiors. Pattern, especially, is very personal and can be very feminine, which therefore is not accessible to all," Chidgey says.

That may be the case but for Missoni, whose distinctive stripes have placed it among world leaders in pattern design, business is booming here and abroad.

Australia is now one of the fastest growing markets for its business, with the range first hitting our shores six years ago.

Fiona Spence, the distributor of Missoni Home throughout Australia and New Zealand and the owner of interiors store Spence & Lyda, says there has been 100 per cent growth year-on-year since she started importing the range. This is mind-boggling, considering cushions can cost more than $500 and a small floor rug goes for $6000.

"At first it was a confronting collection, even for those forward thinkers who were asking for colour," Spence says.

"What we noticed was that people went to the towels first, as a way to introduce colour into their house. Then they realised how fabulous it made them feel, so they [were more confident about moving] into the living room with cushions and then into the bedroom with the bedding collection.

"I also think this collection does incredibly well in Australia, compared to the rest of the world, because we are very much an entertaining nation.

"We have always entertained at home, so for many Australians the home tends to be a reflection of themselves.

"[In contrast] we are in the process of looking at exporting Missoni to China [but] the Chinese don't entertain at home, so it is a difficult market."

Missoni has faith that her interior designs, as with her fashion, one day will become collector's items.

Regardless, she says the success of this new business venture is a bonus in an already long and successful career. "I don't miss the fashion at all.

"There are ages that correspond with things in life and fashion did not correspond with my age any more - it became a duty.

"I was used to thinking of my work as my hobby and this is now my new hobby."

How to feather your nest

Looking to dress up your home? Here are fashion designer turned interior designer Rosita Missoni's tips.

"My houses are full of things I like. The concept of a home should be a nest so bring in all the things you like.

"When I go into a home and see it all perfectly arranged, even though I have a great respect for decorators, [I think] they make it their home, not yours. People have to make an effort to make homes more like themselves. They can be full of mistakes but it is better than a home being too perfect.

"Dare to mix things and experiment. Play with pillows because they are not that expensive.

"People should try to have a spontaneous approach to their home. If you find something you like, don't think you have to change everything in your home to match.

"Flowers and plants can help lift a room.

"Nice objects, at any price, can help you be a little creative in your home."