French scientist Pascal Cotte claims to have reconstructed a portrait which was previously made on the same canvas using a special technology "projecting a series of intense lights" on the painting, as revealed by a BBC report this week.

A reproduction of the earlier portrait Cotte says he discovered shows another woman sitting in a similar way. Her gaze is not as direct as the portrait everyone knows and, most notably, her mysterious smile is missing.

The scientist was given special access to the painting hanging at the Louvre in Paris in 2004 and spent 11 years analyzing it. The French scientist claims he "can peel like an onion all the layers of the painting" and recreate all its phases, thanks to the technique he has developed, called Layer Amplification Method (LAM).

Cotte says the image he found in the hidden layers of the painting does not portray the same person. Experts believe Mona Lisa was a woman called Lisa Gherardini, the wife of a silk merchant who lived in Florence 500 years ago.

Cotte's findings are controversial, however. The Louvre Museum has not endorsed his research. Many scientific teams have been analyzing the Mona Lisa using different techniques, such as infrared and multi-spectral scans and they have come to different conclusions.

Though over-painting an image was common at the time, that does not mean the previous paintings show another woman. "This is the world's most famous painting which, like a celebrity, always makes for a good story. But in this case I think caution is required," explained Will Gompertz, the BBC arts editor, on their website.

Cotte's revelations are part of a traveling exhibition called "Da Vinci - The Genius" which opened in Shanghai on December 8.