Emin does a paint job for the Fiat 500's new model

The Fiat 500 is the car that defined post-war, Continental style. So when the Italian car maker decided to follow in the tyre marks of the Volkwagen Beetle and the Mini by creating a new version for the 21st Century, they faced a challenge: just how do you do you make the ultimate in bijou chic even cooler?

The answer: get Britart phenomenon Tracey Emin to do a paint job on four of them. Emin has painted the cars as part of her mobile exhibition in London Frieze week. Emin examples aside, the Fiats will arrive in the UK in the New Year and the first of the new 500s are hitting the Continent's roads now.

Tracy Emin used one of her customised versions of the car to drive to the Royal Academy of Art's annual dinner, where she was guest of honour. The car, entitled You Go Around Me, featured a drawing of a kneeling, naked woman on the front door in the artist's simple, signature style. Beneath the woman is the stem of a plant, that goes right around the exterior of the car, flowering just above the headlight.

"I really enjoyed working on the Fiat 500, which I refer to as the 'mouse car'", the artist said. Emin deliberately chose not to play up to the size of the car with saccharine drawings, instead opting for more shocking works, featuring naked figures in sexualised positions. "It was tempting to make them even more super-cute, but instead I decided to give them an edge", said Emin.

The series is called "Drawings in Motion", and the four painted cars will drive around central London from 9 October to 21 October, throughout the Frieze art fair. The chauffeur-driven artworks will also be available for art enthusiasts to flag down free of charge to travel between galleries.

The other cars on display, called Love is Love, Dark Dark Dark, and I Told You Not To, are similarly personal works. The designs were all printed on the vehicles using similar technology to photo processing.

Susie Allen of Artwise, who curated the project, said: "Lots of artists have worked on one car, but nobody has ever done a fleet of cars before. Tracy wasn't sure about working with cars at first, but when she heard it was the Cinquecento, she got really excited. Apparently it used to be known as the mouse car, and Tracy loves mice".

One of the motorised artworks will go on sale at an art auction at Phillips de Pury in Victoria on 13 October. Proceeds from the car will go to the charity PEAS, which raises funds for school libraries in Uganda.

Emin is notorious for her daring works and unusual media. In pieces such as Everyone I Have Ever Slept With, a tent appliquéd with the names of her sexual partners, she was accused of shock tactics. This is yet another major show for the successful British artist, who this year represented Britain at the Venice Biennale.

Fifty years since it first took to the roads in 1957, the retro Cinquecento has been launched by Fiat to celebrate the vehicle's anniversary. Production stopped on the last of the original models in 1976 but now Fiat's car factories have rolled out the new one, which will go on sale in the UK in January. It is already being hailed as the must-have design object of 2008.

A distant cousin of its distinctly utilitarian predecessor, British prices for the new Cinquecento are likely to start from £11,000. The redesign includes swanky interior features, such as chrome air vents and brightly-coloured panelling in the same shade as the car's bodywork. As with the new VW Beetle, the car body of the Fiat 500 has been bulked out, and adjusted to make it more aerodynamic.