Banksy's 'Girl With Balloon' diptych up for auction for the first time

A two-part version of Banksy's "Girl With Balloon" painting is seen fetching up to $4.75 million when it goes under the hammer for the first time at a Christie's auction in London later this month.

The rare edition, one of 25 created by the elusive British street artist in 2005, features a young girl in one painting and her heart-shaped balloon in another.

"It's a pretty signature image for Banksy in that he did the first iteration of it on the streets," Katharine Arnold, co-head of Post-War and Contemporary Art for Christie's in Europe, told Reuters as the artwork went on display at the auction house's London showrooms on Friday.

"The Girl With Balloon" first appeared on the streets of London's Shoreditch neighbourhood in 2002, with Banksy creating versions of the painting on London's South Bank in 2004 and at Israel's barrier at the West Bank in 2005.

"There are some iterations of this where you see the little girl with the balloon in the tiny little format of a single canvas," Arnold said.

"Here ... the balloon is already flown away into a second canvas. And of course, that means that she's forever separated from her little heart balloon that she's hankering after."

The diptych has been in the hands of a private UK collector since 2013. It is the first of its kind to go on sale at Christie's, where it seen fetching between 2.5 million and 3.5 million pounds ($3.39 million - $4.75 million).

"It's an image that really is about hope and aspiration, which after the last 18 months that we've gone through is something that we all need more than ever," Arnold said.

Banksy, whose real identity is unknown, rose to fame for sharply ironic outdoor graffiti with political themes. Once a small-time graffiti artist from the English city of Bristol, his art work has become hugely popular and valuable.

"The Girl With Balloon" diptych will be part of Christie's "20th/21st Century: Evening Sale Including Thinking Italian" held in London on Oct. 15.