LONDON — Lucian Freud's portrait of a naked, pregnant Kate Moss is expected to fetch up to $6.4 million when it is auctioned next year, Christie's auction house said.

The near-lifesize portrait of the supermodel, "Naked Portrait 2002," will be included in a Christie's sale of postwar and contemporary art on Feb. 9. It is being sold by an unnamed private collector, the auction house said Thursday.

Freud, 81, is considered by many to be Britain's greatest living artist, and his sitters have ranged from friends and family to Queen Elizabeth II.

The artist, a grandson of psychoanalyst Sigmund Freud, has said he prefers to paint his models naked because "I can see more: see the forms repeating right through the body and often in the head as well."

"One of the most exciting things is seeing through the skin, to the blood and veins and markings."