A drawing of a nude woman that bears a striking resemblance to the famed Mona Lisa may have been done by Italian Renaissance painter Leonardo da Vinci, reports said Thursday.

The charcoal sketch known as the “Monna Vanna” has been held since 1862 in the huge collection of Renaissance art at the Conde Museum at the palace of Chantilly, north of the Paris, where it was housed ever since it was bought by the Duke of Aumale, a city in northwestern France, in the same year for 7,000 francs ($7219.4), a substantial amount of money during that time, the Telegraph reported.

French art experts, who only recently got their hands on the early 16th Century portrait, have found enough clues to suggest that the “drawing is at least in part” by da Vinci, the Agence France-Presse (AFP) reported. It has long been attributed to students of the artist before.  

"The drawing has a quality in the way the face and hands are rendered that is truly remarkable," curator at the Louvre Museum in Paris, Mathieu Deldicque, told AFP. Puncture marks on its edges also suggest that the sketch may have been placed on a canvas for its outline to be traced.

Deldicque added, "It is not a pale copy. We are looking at something which was worked on in parallel with the Mona Lisa at the end of Leonardo's life. It is almost certainly a preparatory work for an oil painting."

Both — the Mona Lisa and the Mona Vanna—are of the same size. Louvre conservation expert Bruno Mottin also confirmed the drawing was from around da Vinci’s lifetime at the turn of the 15th century and was of a "very high quality." He told reporters that tests had already revealed it was not a copy of a lost original painting.

However, Mottin said that while attributing the sketch to da Vinci, “we must remain prudent.”

“The hatching on the top of the drawing near the head was done by a right-handed person. Leonardo drew with his left hand,” Mottin pointed out. “It is job that is going to take some time,” he added. “It is a very difficult drawing to work on because it is particularly fragile.”

Museum curators are looking to find a definitive answer to who the artist behind the sketch is before the 500-year anniversary of Leonardo’s death in 2019, according to the Telegraph report.

Sitting behind bullet-proof glass, the Mona Lisa is Leonardo da Vinci’s most famous painting, believed to have been a commission from cloth merchant and official in Florence Francesco del Giocondo for a portrait of his wife, Lisa Gherardini.

However, there are several rampant theories that the woman in the image could have been da Vinci's mother, lover or even a disguised self-portrait. The enigmatic painting has been the subject of several studies by da Vinci experts who have come up with many revelations. In 2015, for example, a French scientist, Pascal Cotte, claimed he found three hidden paintings beneath the surface of Leonardo Da Vinci's masterpiece using reflective light technology.