I know it when I see it, an it girl, that is.

The it girl is one of fashion's most enduring, if elusive, figures.

Everybody knows what it is, but no one can really define it.

Here are two attempts.

The it factor lives in the girl who doesn't know she's beautiful, who's utterly without

self-consciousness or pretence.

That's from the 1920s, from British writer Eleanor Glinn.

Then there's the it girl with a street smart style and down low attitude.

That's how novelist Jay McInerney famously described actor Chloe Sebeni,

maybe the 90s first real it girl.

At the beginning of the 1990s, the supermodels were larger than life,

still the faces of fashion.

But as the decade moved on, a new set of cool girls slowly started drawing

everyone's eyes off the runway and to the front row of the show.

They were the socialites, the starlets.

They were the girls who knew how to dress as well on the street as they did in the movies.

They sold us glamour and hollywood and we bought it.

By the end of the 90s, hollywoods it girls were modelling high fashion for the masses

on television, the movies and under a new kind of spotlight.

The red carpet and a Vogue cover girl was as likely to be an it girl as a supermodel.

They became the walking symbols of 90s fashion's most coveted ideals for better and for worse.

They were cool, pretty, famous but most importantly, they were it.

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