Banksy has revealed how he created the self-destructing painting that was sold for more than €1.1million.

The piece, Girl With Balloon, is one of Banksy's most well known images. It shows a young girl reaching up towards a bright red heart-shaped balloon. It was sold at Sotheby's Contemporary Art Evening Sale on Friday night. The auction house said that the painting and been signed and dedicated, with the vendor getting it from the artist in 2006. The winner bid £860,000 (€977,650) - £1,042,000 (€1,184,550) with the buyer's premium - over the phone around 9pm. Shortly after, it appeared to automatically "self-destruct". https://www.instagram.com/p/BomXijJhArX/ The artist has now explained how the "self-destructing" painting was created - and showed the moment it went through the shredder in front of the confused crowed. The clip, shared on Banksy's official Instagram account, begins:

"A few years ago, I secretly built a shredder into a painting in case it was ever put up for auction."

There are shots of the shredder being built into the frame, before it cuts to Sotheby's auction house on Friday night. https://www.instagram.com/p/Bokt2sEhlsu/?utm_source=ig_embed The footage appears to be from various spots throughout the room, as the auctioneer takes bids. The moment he hits the hammer, a beeping fills the room - and the painting begins to emerge from the bottom of the shredder. Alex Branczik, Sotheby's senior director and head of contemporary art in Europe, said (via the Financial Times):

"It appears we just got Banksy-ed. “We have not experienced this situation in the past . . . where a painting spontaneously shredded, upon achieving a [near-]record for the artist. "We are busily figuring out what this means in an auction context."

A spokesperson for the auction house told the publication that they have been in touch with the purchaser of the piece, who was "surprised by the story." They are discussing the next steps to take. Girl With Balloon first appeared on Great Eastern Street in Shoreditch, London, in 2006.