Freud's self-portrait sparks search for identity of nude

It is hard not to imagine a smile crossing the craggy features of Lucian Freud as his new work is unveiled to the public.

It is hard not to imagine a smile crossing the craggy features of Lucian Freud as his new work is unveiled to the public.

At 82, the painter has depicted himself pausing while painting in his studio as a young woman in the nude clutches his leg. It is entitled The Painter Surprised by a Naked Admirer.

As is common with Freud, there is no clue to her identity in the title of the work that is being exhibited at the National Portrait Gallery London for three weeks from today before going on show in Venice during its Biennale.

Given the artist's somewhat rakish reputation with women - and, most particularly, younger women - it is bound to unleash a furious search for her identity.

One specialist said, whoever she was, she had modelled for the artist for some considerable period in developing the work which Freud began last summer. "I'm not aware of other paintings where she has appeared," the source said.

Many of Freud's models have been lovers, including Emily Bearn, a journalist more than 50 years his junior with whom he lived for several years. In a BBC1 documentary in the Imagine series last year, Anne Dunn, another former lover, spoke of "being used by Lucian" as if his relationships were part of his creative process. But he has worked with other sitters including members of his family and celebrities such as Kate Moss and Jerry Hall.

This painting was begun last summer and completed only within the past few weeks. It pays deliberate homage to The Studio of the Painter, 1854, by Courbet in which the poet Baudelaire, a naked model and others play court to a painter.

William Feaver, Freud's friend and biographer who wrote on the portrait for the London Evening Standard, said only that Freud regarded the woman as his muse. "Any idea that it is a kind of male artist and repressed, poor female is, if anything, being made fun of. They both have a sense of humour."

The work will act as a prelude to a major exhibition of self portraits at the Portrait Gallery planned for October. Theshowwill include a Freud from 1967 to be hung alongside works by artists such as Rembrandt, Velazquez and Van Gogh.