Lucian Freud's Woman Smiling up for sale
A Lucian Freud painting of his ex-wife, Suzy Boyt, is expected to fetch up to £4.5m when it is auctioned in London.
Woman Smiling, which Freud painted in 1958 and 1959, will go under the hammer at Christie's on 28 June.
The auction house said it had pioneered the use of "thick, expressionist brush-strokes" for which he is well-known.
Freud 's 1995 piece Benefits Supervisor Sleeping set the world record price for a living artist when it sold for $33.6m (£21m) in New York in 2008.
Woman Smiling was once owned by the wife of James Bond creator Ian Fleming, who sold the piece in 1973 for just over £5,000.
The painting of Boyt - mother to five of Freud's children - has been in a private collection since 1985.
Five early drawings by the artist are also up for sale in June's Post-War and Contemporary Art auction.
The pieces, from the collection of Kay Saatchi, include a pencil drawing, Boy With Pipe, as well as some detailed studies of animals.
Woman Smiling, together with the five works on paper, will be exhibited in Moscow on 2 and 3 April.
Francis Outred, head of post-war and contemporary art at Christie's Europe, hailed Freud as "one of the artistic giants of the post-war era".