A French scientist who has been using technology to study Leonardo Da Vinci’s Mona Lisa has claimed there is a second portrait hidden behind the renowned painting. Pascal Cotte’s reconstruction of the second painting shows a woman who closely resembles the Mona Lisa sitting in a similar position, but unsmiling and looking to the left. Mona Lisa’s direct gaze and enigmatic smile have long been considered the most intriguing aspects of Da Vinci’s celebrated sixteenth century work. The Louvre in Paris, where the painting is displayed, has not commented on the discovery, saying Cotte was not a part of their scientific team, the BBC reported.

Cotte said his discovery could challenge the widely accepted theory that the Mona Lisa is a painting of Lisa Gheraldini, the wife a Florentine silk merchant. “The results shatter many myths and alter our vision of Leonardo’s masterpiece forever,” Cotte said. The discovery has met with a mixed response, with some art critics saying they are skeptical, saying it is common for there to be underpaintings in many such portraits.