A self-portrait created by Jean-Michel Basquiat will be auctioned off by Christie’s London on March 7 as part of the famed auction house’s Post-War and Contemporary Art auction after spending the last 25-plus years as part of U2 bassist Adam Clayton’s private collection.

Clayton picked up the 1982 Basquiat piece in New York in 1990 while U2 was recording its seventh studio album, “Achtung Baby.”

“There was a group of them,” Clayton said in a statement that goes along with the sale of the work. “There was Basquiat, there was Haring, and obviously Warhol was the granddaddy of the whole movement. The idea that these young painters without any gallery experience could make their mark on the streets of New York—could go to the hippest night clubs, could mix with musical culture, was very exciting to me. It was where I came from—I always thought music and art went hand in hand together.”

The untitled Basquiat portrait will spend the next few weeks on a global tour before it heads to London for the sale. It is estimated to fetch between $1.2 and $1.8 million.

Clayton and U2 are a few months away from setting out on a tour revamping the famed The Joshua Tree album. The Joshua Tree Tour 2017 starts in May and ends in August, with many of the dates already sold out.