Mention Flaming June or Frederic Lord Leighton, and people squint. Show them the image on your iPhone, the painting of the sprawled, sleeping woman in a see-through saffron gown, and their eyes get wide with recognition.

They’ve seen Jessica Chastain as Flaming June on the December 2013 cover of Vogue. Faye Dunaway lounging by the Beverly Hills Hotel pool, pensive after her Oscar for Network. Not to mention Flaming June T-shirts, coffee mugs, wall clocks, mouse pads, luggage tags, phone covers, jigsaw puzzles, and Christmas ornaments in gift shops everywhere. This month, the ubiquitous painting is making its New York debut at the Frick Collection, and there are new details that point to the identity of the woman in the saffron gown.

In 2014, Bamber Gascoigne, onetime host of British quiz show University Challenge, unexpectedly inherited West Horsley Place, a crumbling country house, from his 99-year-old aunt, the Duchess of Roxburghe. Many rooms had been shuttered for decades, and Gascoigne spent months uncovering treasures, from Victorian footmen’s liveries to the Duchess’s miniver-trimmed coronation robes. Behind an anteroom door, he found a pencil-and-chalk drawing of a woman’s head: the central study for Flaming June, which had been lost for 120 years.

The survival of the painting is as much of a fluke. Leighton completed Flaming June in 1895, during the final months of his life. He was then president of the Royal Academy of Arts, the gatekeeper of high Victorian taste, and Flaming June the highpoint in a group of paintings of monumental, classicized women. “It’s really all about formal beauty and the combination of that ingenious composition: the circular figure within the square canvas, and the classical setting that gives it a sense of timelessness,” said Susan Grace Galassi, senior curator at the Frick Collection, of Flaming June.

The woman’s body, bathed in sunshine, offers little clue to who she is or what she is dreaming about, except an oleander blossoming over her head. “It’s a seductive flower, but it’s highly poisonous,” Galassi explained. “So seeing the bouquet of oleanders in the painting has raised the question of whether the sleeping beauty is really more of a femme fatale.”

The Roxburghe drawing, which is coming up for sale at Sotheby’s in July, suggests an answer. While the features of the woman in the painting are of a non-specific beauty, the face in the drawing belongs to Dorothy Dene, Leighton’s favorite model and muse. Born Ada Alice Pullan, she changed her name to the more theatrical Dorothy Dene, hoping her symmetrical features and long, lithe body would attract the attention of artistic personalities like Leighton. Dene posed for numerous paintings during the artist’s final 15 years, while also working as an actress. Leighton paid for her elocution lessons and even established a trust for her after his death. “The press absolutely speculated that they were about to be married,” said Daniel Robbins, senior curator of the Leighton House Museum in London.

Though other models have been suggested for Flaming June, including Dene’s contemporary Mary Lloyd, the drawing’s upturned mouth, set-apart eyes, and voluminous curls all point to Dorothy Dene—as in the paintings Crenaia (1880) and Clytie (1895), which are practically portraits. “While one would assume it was her in the painting,” Robbins says of Dene and Flaming June, “her features in the painting have been turned into a more generic Leighton expression; [but] it’s clearly her in the drawing.”