A rare Picasso masterpiece with a concealed image on the reverse has been sold for £45m - a record for a painting from his prized Blue Period.
The oil-on-canvas painting entitled La Gommeuse easily beat the £30m estimate at Southeby's New York.
It depicts a naked woman on the front and a previously unseen portrait on Picasso's friend Pere Manach, wearing an exotic headdress in with his head on the body of a female dancer, on the back.
The image remained hidden under the lining of the main painting for a century until it was uncovered during conservation work in 2000.
Picasso painted La Gommeuse after his friend Carlos Casagemas's suicide in 1901, and as he and Manach threw themselves into the debauchery of Paris life.
Works from the painter's 1901-1904 Blue Period rarely come up for sale.The painting had been in the private collection of US billionaire and art collector Bill Koch.
Simon Shaw, co-head of Impressionist and modern art worldwide, called it "a small sale that packed a real punch".
He added: "Each season Picasso has the remarkable ability to surprise, and tonight was no exception, with the unusual appearance of two Blue Period works, which set new benchmarks - both in oil and on paper."