Ron Mueck's “Big Baby” sculpture appears to look round at Jenny Saville's painting “Interfacing” at the Masterpieces Exhibition at Christie's on June 13, 2011 in London, England. The painting and sculpture feature in the exhibition, open to the public from 13th–15th June 2011, which showcases some of the Ј250 million worth of art for sale over the next four weeks. Artists including Michelangelo, Gainsborough, Goya, Stubbs, Monet, Picasso and Renoir are represented. (Photo by Peter Macdiarmid/Getty Images)

An employee looks at George Stubbs' painting “Gimcrack on Newmarket Heath, with a Trainer, a Stable-Lad, and a Jockey” at the Masterpieces Exhibition at Christie's on June 13, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

A visitor looks at Pablo Picasso's painting “Jeune fille endormie” at the Masterpieces Exhibition at Christie's on June 13, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

Visitors examine “A male nude seen from behind” by Michelangelo at the Masterpieces Exhibition at Christie's on June 13, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

A set of Four Empire Ormolu-MountedChinese Porcelein Vases are displayed next to “The Dance of Salome” by Gyula Tornai at the Masterpieces Exhibition at Christie's on June 13, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

Gainsborough's “Portrait of Miss Read, later Mrs William Villebois” is displayed at the Masterpieces Exhibition at Christie's on June 13, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

Visitors examine Adriaen de Vries' sculpture “Mythological Figure Supporting the Globe” at the Masterpieces Exhibition at Christie's on June 13, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

The “Imhof” prayer book by Simon Bening is displayed at the Masterpieces Exhibition at Christie's on June 13, 2011 in London, England. The book, estimated at Ј1.5-2 million, features in the exhibition, open to the public from 13th - 15th June 2011, which showcases some of the Ј250 million worth of art for sale over the next four weeks. (Photo by Peter Macdiarmid/Getty Images)