Banksy's first film unspools at Sundance

Notoriousgraffiti artist Banksy could be pulling his biggest prank ever at the Sundance Film Festival with the premiere of his first-ever film.

Exit Through The Gift Shop has been billed as a film by the British artist, who has evaded being identified and often leaves his art in public places.

Narrated by British actor Rhys Ifans, the film premieres at the Park City, Utah, festival on Sunday night.

According to the Sundance description, "L.A.-based filmmaker Terry Guetta set out to record this secretive world in thrilling detail. For more than eight years he travelled with a backpack through Europe and America. After he met a British street artist known only as Banksy, things took a bizarre turn."

There's much anticipation and secrecy surrounding the film with the director of Sundance, John Cooper, himself wondering whether it could be real or a stunt.

"[It's] a warped hybrid of reality and self-induced fiction while at the same time a totally entertaining experience,"Cooper told BBC News.

Apparently, the artist does speak on camera for the first time ever but it has not been revealed whether his identity is divulged.

Four stencils, reputedly by the artist, turned up this week on walls in Park City.

In a statement to the BBC, Banksy says the film is "the story of how one man set out to film the un-filmable. And failed."

Banksy has built his reputation on myth.He's known for sneaking into major art exhibits and placing his own works within them.Once, he smuggled a blow-up doll dressed in the orange overalls of a Guantanamo detainee into Disneyland.

He also stenciled a scene onto the wall separating Israel from the West Bank town of Bethlehem in 2007.It showed an Israeli soldier checking the papers of a donkey.

Back in 2008, a British newspaper claimed to have unmasked Banksy as a middle-class boy from Bristol who is now in his mid-30s. The claim was never substantiated.