Banksy has reworked a Nazi figure into an oil painting he bought from a charity shop in New York.
After vandalising the painting, he gave it back to the shop, where it is now being auctioned off for almost £200,000.
The Bristol-based artist has called the oil painting, which depicts a Nazi officer looking out onto a lake, "The banality of the banality of evil".
Banksy, who completes his month-long "artist’s residency" in New York today, bought the original painting from The Housing Works thrift store for $50 (£31).
The artist signed his name alongside original artist K Sager, and the painting has been put up for auction online on biddingforgood.com.
The money raised at the auction will go to The Housing Works, which helps to fund homelessness and Aids initiatives.
The online auction, which is due to close tonight, has already attracted a bid of $310,400 (£193,000).
The painting can currently be seen in the window of the charity shop on New York's East 23rd Street.
Writing on his website about the donation, Banksy only said: "A thrift store painting vandalised then re-donated to the thrift store."
Shortly after the painting was handed into the shop on Tuesday, staff received a phone call from one of the artist's team explaining that the painting was an authentic Banksy.
Staff said the painting had been hanging there for several hours without attracting any attention before Banksy posted an announcement on his website about it.
Works by the artist have popped up around New York City in October, including a statue of Ronald McDonald and a tribute to the twin towers.
Earlier this week, the artist posted an opinion piece on his website criticising the design of the new World Trade Centre, describing the building as a "shyscraper".
He said: "Remarkably for such a tall structure, One World Trade lacks any self-confidence. How does it stand up without a spine? It looks like it never wanted to be built in the first place.
"It reminds you of a really tall kid at a party, awkwardly shifting his shoulders trying not to stand out from the crowd. It's the first time I've ever seen a shy skyscraper."
For what appears to be his last piece of work in New York this month, the artist spray-painted his name "Banksy" onto a building in the middle of the Long Island Expressway in Queens.