A painting of a gay couple is expected to go for as much as $38 million at auction next year.

Created by openly gay British pop artist David Hockney back in 1969, the work features a rendering of Henry Geldzahler, a famous curator for the Metropolitan Museum of Art, and his partner at the time, painter Christopher Scott.

The portrait, titled after the couple in it, was part of a “turning point” in Hockney’s career, during which he was motivated “to create an ambitious, groundbreaking series,” according to Forbes. The series ultimately contained seven portraits, and each featured two people in a domestic setting not paying attention to each other.

This particular part of the series is special due to Hockney’s close friendship with Geldzahler, who died of cancer in 1994. The curator became a source of inspiration for many artists, not just Hockney.

Christie’s, who will auction the portrait at their London branch in March, describes the painting as including “a composite of elements in each man’s life: the Art Deco sofa from Gelzahler’s New York living room, the view from Scott’s study, and a vase of tulips thought to symbolise the artist himself.”