Robbie 'wouldn't put clothes back on'

Photographer Mario Testino says Robbie Williams was reluctant to put his clothes back on after he snapped him in the nude.

The star was snapped naked for the cover of fashion magazine Vogue with model Gisele Bundchen.

The singer eventually popped his clothes back on but only after telling Testino he'd happily "be nude all day".

Celebrity and portrait photographer Testino said : "It was an experience. I told him 'Robbie you will only need to be nude for 10 minutes'. And he said 'No, I really don't care. I'll be nude all day'."

An image of Williams appears in the exhibition - Mario Testino: Portraits which opens at the National Portrait Gallery in London - with the bikini briefs that Bundchen wore draped across his face.

Other stars whose images appear in the gallery include Meg Ryan, Gwyneth Paltrow and a whole room devoted to one of his favourite subjects Kate Moss, whose career he has tracked over the past decade.

One of his most famous sitters has been Diana, Princess Of Wales whom he captured in a series of elegant shots for Vanity Fair.