"A fashion picture is a portrait; just as a portrait is a fashion picture." Irving Penn, 1950.

The venue is small but the perfect environment for Face of Fashion, the new photographic exhibition at the National Portrait Gallery. Once you walked in, you know that all the 'faces' watching at you are VIPs from the fashion industry. The Open room shows Kate Moss and Christina Ricci by Mert Alas & Marcus Piggot. And again Kate Moss and Kate Moss, the queen of the exhibition, the fashion icon of the 21st Century (and the one before since Calvin Klein spotted and selected her for the famous underwear ad). The second room is still dedicated mainly to Kate Moss (Obsession ad for Calvin Klein circa1993), but also appear a very intriguing Julianne Moore on broken mirrors (for W Magazine), a very young Milla Jovovich (1996) and more confirmed fashion icons such as Catherine Deneuve (2003). Face of Fashion is a major exhibition focusing on the portraits of five outstanding fashion photographers from Europe and America: Mert Alas & Marcus Piggott, Corinne Day, Steven Klein, Paolo Roversi and Mario Sorrenti.

In the contemporary fashion world, models, actors, musicians and designers frequently swap places. The exhibition highlights the relationship between fashion and celebrity and illustrates the extraordinary intimacy that often develops between photographer and subject.

The photographer Steven Klein says about himself that he is 'a private person not an exhibitionist'. He is a 'person who lives for the future, not the past'. And you can see his words very well represented in his work. Corinne Day, an ex-model herself who has famously worked consistently with Kate Moss for 15 years, collaborates closely with her subjects developing a close rapport which results in some of the most candid portraits in fashion. Her portraits themselves generated much of the anti-glamour zeitgeist of the 1990s.

Two Italian names amongst the Face of Fashion work: Paolo Roversi (Italian who lives in Paris) and Mario Sorrenti who was born in Naple in 1971 but has lived in New York since age of 10. Those photographers made their trademarks by photographing supermodels, film stars and famous people in general and picked two of the most glamorous capitals in the world as 'home': Paris and New York.

Mert Alas and Marcus Piggott are famous for their offbeat but glamorous portraits of stars such as Kate Moss, Uma Thurman and Drew Barrymore. Producing a strange, and at times anxious, intensity in their constructed images, they create pure fantasy for the modern age.

Even if the space could be bigger to host all these big names, it seems the right size to make the exhibition cosy and warm. The list of 'beauties' is never ending at Face of Fashion. Natalie Vodianova, Juliette Binoche, Vanessa Paradis, Jude Law, Charlotte Gainsbourg, Lauren Hutton, Wynona Ryder, John Frusciante, Matthew Barrey and Jasper Johns.

It is the first exhibition of its kind, celebrating the innovation and diversity of current fashion portraiture. Fashion photography dominates our visual culture. Never has it been so prevalent, pervasive and wide-ranging, incorporating as subjects not only the most popular professional models but also the greatest actors, musicians, sporting heroes, filmmakers, designers and dancers. With the boundaries between advertising, editorial and fine art now blurred, the world's most famous fashion photographers are shaping our ideas of beauty, sexuality and fame.

Sometimes supporting a glamorous aesthetic, sometimes subverting it, fashion photography is at the height of its powers and its leading exponents among the great image-makers of our time. Mert & Marcus, Corinne Day, Steven Klein, Paolo Roversi and Mario Sorrenti are each unique and distinctive in style. Together these portraits explore the intimacy that exists between photographer and the subject and how this relationship, sometimes perceived to be exploitative, frequently empowers both parties.