Bill Koch, an oil-refining billionaire, just sold a Pablo Picasso reverse painting to Swiss dealer Doris Ammann for $67.5 million during the Sotheby auction.

The 1901 painting, "La Gommeuse," or "The Cabaret Dancer," was created during Picasso's "Blue Period," when he was 19 years old and grieving for a close friend who committed suicide. He depicted a woman whose "very body defines the perverse beauty of the age," the auction house said, AFP reported.

Ms. Ammann got two Picassos for the price of one because conservators have discovered another scene Picasso painted on the reverse of the canvas, The Wall Street Journal noted.

It was in 2000 when Koch found out about the painting on the other side of the canvass. It was a comical image of a frolicking nude man believed to be Picasso's roommate, Pere Mañach.

"It gives a wonderful added dimension. The value sits in the front, but it [the reverse] does give you a glimpse into what Picasso's life must have been like in 1901 when he had just arrived in Paris and was still a relatively impoverished artist," said a Sotheby representative, according to The New York Post.

The auction house also sold Koch's Monet "Nympheas" (water lilies) study in oil for $33.85 million, clearing its minimum pre-sale estimate of $30 to $50 million, Bloomberg reported.