BERLIN (REUTERS).- British street artist Banksy's mural "Every Picture tells a lie" was rediscovered in Berlin this weekend after a gallery layered it in paint eight years ago to create space for new works.

Banksy, whose identity is unknown to the public, is a world-renowned graffiti artist. His newly recovered mural was spray-painted in 2003 for an exhibit at a contemporary art gallery in Germany's capital.

The mural was excavated as part of an art project by Brad Downey, a Berlin-based American artist, whose exhibition is titled "What Lies Beneath" and focuses on layers of paint.

"The unearthing is Downey's project -- he wanted to play with it," said Stephane Bauer, head of the Kunstraum Bethanien gallery, where the Banksy work is being displayed.

Downey, who also took part in the 2003 exhibit, remembered Banksy's work and wanted to uncover it for his 2011 project.

Under Downey's careful instructions, restorers uncovered the artwork, which portrays winged-soldiers with smiley faces carrying guns. The words "Every Picture Tells a Lie" are scrawled in blood-red paint above them.

Banksy first drew attention in the early 1990s with controversial stenciled graffiti, seen by some as subversive and by others as satire.

His commercial pieces have sold for huge sums -- the most famous of which is "Space Girl and Bird," which was auctioned in 2007 for 288,000 pounds, or close to half a million dollars.

The gallery is unsure of what will happen to Banksy's work once Downey's exhibit ends on Oct 23rd. It could go back to hibernating behind white-washed walls -- that is, if someone doesn't try to buy it first.

But Bauer said it was difficult to say how much the Banksy is worth. "I don't think it can be worth much since it is just one layer of paint among many," Bauer told Reuters.

Gareth Williams, who has helped sell Banksy pieces in the past, said that in order to price one of his artworks, details are first sent to the artist's agency for authentication before the pieces can sell.

Williams, head of the Urban Art department for Bonham's Auction House in London, said that if the mural found in Berlin is authenticated, Bonham's would be happy to help the gallery owners sell it.

(Reporting By Natalia Drozdiak)