X-ray studies have revealed that underneath Amedeo Modigliani’s masterpiece Portrait of a Girl hides another portrait of yet another girl. It has been concealed in plain sight for over a century.

The hidden portrait emerged during a technical research study initiated by the Tate Modern in collaboration with international museums and art historians. While the identities of the two girls cannot be confirmed, the Tate suggests that the hidden portrait may, in fact, have been a painting of Modigliani’s former lover and muse, Beatrice Hastings. The dates line up: Hastings and Modigliani had a short and tumultuous relationship that ended within two years, around 1916. The Portrait of a Girl as we know it now was completed in 1917. So did the artist really want to paint over his ex?

The unexpected finding was published this week in Burlington Magazine. Nancy Ireson, the curator of international art at the Tate Modern, told the Guardian that though it is a nice idea, it does remain, at this point, only a hypothesis. “It’s quite interesting to think that he might have painted her out. So often, when you see a canvas reworked, it’s impossible to actually read the image beneath,” she said. “To be able to make out the figure is exciting. It’s almost a full-length figure.”

Kenneth Wayne, director of the Modigliani Project and a Modigliani scholar is not convinced. “It is hard to tell if the phantom image below is indeed Beatrice Hastings,” he told artnet News via email. “It’s 50-50. She is usually depicted with a rounder face.”

Both Hastings and Modigliani suffered from alcoholism and drug abuse, and their relationship has been described as passionate and combative. The ex-partner and muse was the subject of several of his portraits.

Hastings, who was a writer, wrote a surrealistic novella about her relationship with the artist while they were together titled Minnie Pinnikin. She read excerpts of it at a public event in 1916, but the manuscript was then lost for the rest of the century. Dr. Wayne discovered it again in 2001 buried within MoMA’s archives.

Both their lives came to tragic endings, with Hastings taking her own life in 1943. Despite being one of the most revered (and often faked) artists, Modigliani spent much of his short life without much money, and even famously tried to sell the entire contents of his studio for £100 ($138). He died at the age of 35.

Portrait of a Young Girl is currently on view at the Tate Modern, as a part of their current exhibition dedicated to the artist, on view until April 2, 2018.

Amedeo Modigliani’s Portrait of a Girl (1917). Courtesy of Tate Modern. © Tate.