"A fashion picture is a portrait just as a portrait is a fashion picture," said legendary style photographer Irving Penn.

This intriguing show, featuring original work from five photographers - some unpublished, some seen in magazines from Vanity Fair to Pop, The Face to Harper's Bazaar - explores the links between the two fields.

See more pictures from the exhibition here

The uninspiring opening section by Mert Alas and Marcus Piggott is redeemed by the jewel-like Doll, featuring the porcelain face of Tanya Dziahileva, Kate Moss's recent Dietrich spoof, "Dior Boy" and the implied violence of Christina Ricci's smudged lipstick.

In the main gallery, Mario Sorrenti's large, classy, commercial portraits prove how success hinges on the subjects' involvement in the shoot: Catherine Deneuve lies in furs in a park; a New York performance artist is bound in elastic; the boy DiCaprio plays monsters.

His famous Obsession ad, featuring a naked Kate Moss, leads us to Corinne Day's landmark sessions in which the symbiosis between subject and photographer was paramount.

Day's teenaged Moss, with braids and freckles, exhibits the unadorned beauty that led to the contrived anti-glamour of Day's later Vogue shoot - where Moss wears skimpy knickers and vest - which launched the now incredible criticisms of "heroin chic".

Steven Klein's 21st-century tableaux involving A-list stars are the antithesis of Day's intimate honesty. His collaboration with Madonna (a crinolined Queen Elizabeth and corseted dancer, from her last tour) led to more interesting cinematic games with Brad Pitt and Angelina Jolie which resemble film stills: the noir intrigue of Pitt carrying a limp Jolie into a room; an epic mystery with Jolie on a bed and Pitt drinking beer outside.

Symbolically outside of the exhibition (and outside of fashion), Corinne Day's recent monochrome headshots of Kate Moss are again stirring controversy: now for unmasking the effects of time and lifestyle on the perfect model. It will be the most talked-about, least fashion-based exhibit.

• Until 28 May. St Martins Place, WC2. www.npg.org.uk