'The show was definitely a boost in my career, but not everyone thought so,' she says, laughing. 'At the end of the series, I asked the girls to rate the wardrobe fittings from one to 10. Sarah Jessica Parker gave it a 10 or 12, but Cynthia [Nixon] gave me a six.

'Regardless of what people say, I look at it like a game of poker: you get a hand and if you're lucky, you win. I had a great show and great characters. I just brought another element to it. It was the greatest thing that happened to my career, but I didn't feel like my life was hinging on the success or failure of the show. Its success was an added bonus.'

Success is something that has come easily to Field during her 40-year fashion career. The daughter of European immigrants, she was the first American-born generation in her family and grew up in New York, studying liberal arts at New York University (NYU) in the late 1950s and early 60s. Her family were retailers and she chose a similar field, working in a department store after college. In 1966, she opened an eponymous boutique catering to young, trendy fashionistas.

'It was always young and up-to-the-minute and was always about young people,' she says. 'It was on NYU's campus, and all the schoolkids came. We had clubbers and drag queens - anyone who was young. As time moved on, we kept up with things and after five years, I moved to another location [where the store remained until 2000].'

During the 70s and 80s, Field's business expanded to include wholesale and eventually her own line of products (which are available now in Hong Kong at On Pedder). But she says it took her five years to get the design right.

'I never enjoyed the design process. I only enjoyed seeing items in my store. We had a name, but we needed a proper designer and that wasn't my job. I knew what I wanted creatively but I was in charge of looking after the business.'

Field's move into costume design didn't come until later in her career. 'In the mid 80s, I was feeling a little bored and was running out of inspiration,' she says. 'A friend of mine, Candy Pratts Price [from style.com], was consulting on a movie that was called Lady Beware, starring Diane Lane as a window designer. The director needed someone who knew the clothes and so she recommended me. He hired me with no experience and that was the beginning.'

Field remembers struggling with movie logistics and protocol. 'It was scary for a moment, but I got over it. It was less stressful than working in retail. And the pay ... I couldn't believe they wanted to pay me all that money to dress people. It was brilliant and wonderful. This was my reward after slugging it behind the counter. It was perfect. I would go and do a movie and then go back to my shop re-energised.'

A series of films soon followed, including Miami Rhapsody (where she met Parker), The Substitute and Dear Diary. Her talents were recognised in 1989, when she received an Emmy for outstanding costume. By the time Parker asked her to join the Sex and the City team she was already an accomplished costume designer, with two successful careers under her belt.

'Styling is being able to look at a person and tell them what they look good in,' she says. 'You have an idea in your head, but the person is essential. I like working with a script because it gives you a background to work from. In the end, you have an actor playing a character and you're there to help them play that character.

'It's not about making a trend. Creating a phenomenon, like with Sex and the City, wasn't the intention - it just happened. We don't make trends. People would ask me what the next best thing was, but I had no idea. I'm always asked to do a makeover and I shy away from them because style comes from within. Clothing and jewellery are adornments, but they're not going to create a person's style. The person has to be comfortable in what they're wearing, otherwise they won't look good. You have to be able to read people.'

Field is also keeping herself busy with projects such as: designing collections for the likes of Candie's, Pro-Keds and Rocawear; working as creative director for Japanese brand Smacky Glam; and doing the costumes for a film with Sarah Michelle Gellar called A Girl's Guide to Hunting and Fishing. She recently closed her Hotel Venus store and opened a new outlet on the Bowery in New York that seems likely to become just as popular as its predecessor.

But the big news is her work on The Devil Wears Prada (due for release in June), a film loosely based on a young girl's experiences in the cut-throat world of fashion.

'It was so much fun,' Field says. 'The prize was to work with Meryl Streep - she didn't disappoint. She met every mark. She was completely down-to-earth, funny and very smooth and secure in herself.

'Working on a movie is so different from editorial. It's a story, not just a fashion show. That's what I love. It's a new dimension. Together, as a team, we're creating a story. That's what it's all about.'