(Bloomberg News) A Francis Bacon self-portrait is estimated to raise more than 20 million pounds ($31.3 million) at an auction in London.

Bacon's 1962 "Study for Self-Portrait" will be included in Christie's International's June 27 sale of postwar and contemporary art. The auction house announced the sale in an e- mail today and wasn't prepared to divulge the name or nationality of the seller.

The gold-framed canvas shows Bacon sitting on a bed. The expressionistic face is set on a cross-legged figure derived from a John Deakin photograph of his friend Lucian Freud that the artist kept in his London studio. It's one of 12 floor- length self-portraits, four of which are now in museums, said Christie's.

Another portrait from the same series sold for 21.6 million pounds at Sotheby's, London, in June 2007.