Freud, his daughter, and a £2m price tag

Bella Freud is a fashion designer of international acclaim, but in a portrait expected to make up to £2.2m at auction this summer she is seen vulnerable and naked, apparently self-conscious at being under the scrutiny of her famous father Lucian.

The portrait will go on sale at Christie's London on 23 June. It comes from a series of paintings of all his daughters - Rosie Boyt, Esther Freud and Bella - in the early 1980s.

A Christie's spokesman said it was Freud's way of getting to know them more closely after what were often years of absence while they were growing up. "The naming of the sitters, something which Freud rarely does, was also a way of publicly acknowledging his children," he added.

But Bella seemed less happy than some of her siblings, the spokesman said. "The pose of Bella, slightly self-conscious, almost to the point of sheltering herself, seems to suggest that, unlike her sister Esther she was less comfortable being naked under her father's famous all-seeing eye than others."

Freud, however, saw nothing strange in using members of his family as models. Asked whether it was odd to paint grown-up daughters this way, he said: "My naked daughters have nothing to be ashamed of."

Freud, the 82-year-old grandson of Sigmund, has become a highly collectable artist. Christie's broke the record price for a Freud twice on 9 February this year. Naked Portrait 2002, of the pregnant model Kate Moss, sold for £3.9m, then the 1962-3 Red Haired Man on a Chair realised £4.1m.