IT’S quite possibly the biggest prank in art history.

Mysterious street artist Banksy rigged one of his best-known works to self-destruct minutes after being sold at auction for $A1.7 million.

The 2006 work Girl With Balloon was the final item in an auction at Sotheby’s in London on October 5.

Shortly after the bid was called, an alarm sounded inside the frame and the painting started to shred to pieces in front of shocked onlookers.

In an intriguing Instagram post, Banksy has revealed how he carried off the biggest art hoax ever.

The British artist — whose identity has long been the topic of debate — quoted Picasso in his post: “The urge to destroy is also a creative urge”.

In the accompanying video, he showed a shredder being fitted to the frame of the painting in a workshop.

The footage opened with the caption: “A few years ago, I secretly built a shredder into a painting.”

The clip shows a hooded figure putting the finishing touches on the device, before text appears on the screen saying: “In case it was ever put up for auction.”

Despite accusatons on social media that the stunt was a set-up, Sotheby’s maintained it was not in on the prank.

“It appears we just got Banksy-ed!” Alex Branczik, the head of contemporary art, Europe said.

“He is arguably the greatest British street artist, and tonight we saw a little piece of Banksy genius,” he said.

“We are busy figuring out what this means in an auction context.

“The shredding is now part of the integral art work. We have not experienced a situation where a painting has spontaneously shredded, upon achieving a record for the artist.”

The move has also been praised as “genius” by fans.

The Financial Times reported the vendor selling the piece had acquired it from the anonymous artist himself. It’s been pointed out that the stunt would have required Banksy or someone working for the artist to be in the room to activate the shredder.

“A man dressed in black sporting sunglasses and a hat was seen scuffling with security guards near the entrance to Sotheby’s shortly after the incident,” The Art Newspaper claimed.

It’s unclear what will happen to the artwork from here but Mr Branczik said it’s possible that it was more valuable now.

“It’s certainly the first piece to be spontaneously shredded as an auction ends,” he said.