A painting by Lucian Freud, grandson of the famed psychoanalyst Sigmund Freud, depicting a London clerk nude fetched $39 million at a Sotheby's auction in London on Wednesday. The painting, titled "Sleeping by the Lion Carpet," was created between 1995 and 1996.

The model, Sue Tilley, who was 35 years old when the portrait was painted, is now 69. She was working as a supervisor at an employment office and part-time as a London nightclub clerk when Freud, then 70, invited her to pose for him. Tilley told The Wall Street Journal that she agreed to pose because Freud was "funny and bought us nice food."

Freud, who died in 2011, paid Tilley 20 pounds per day to pose, which amounts to approximately $85 in today's currency. The payment was later increased to 35 pounds as Freud requested her to continue posing for multiple paintings, each requiring months to complete.

"Sleeping by the Lion Carpet" features Tilley reclining in a chair with an embroidered tiger in the background. Art connoisseurs consider it the most significant work in the series of four portraits Freud painted of Tilley. These four paintings have previously sold for a combined $129 million.

Tilley expressed satisfaction with the sale, humorously stating, "I figure I’m probably worth about £100 million."