HER mysterious smile has captivated art lovers for 500 years, but now an expert claims to have revealed a secret hidden underneath Leonard da Vinci’s famous masterpiece.

    Pascal Cotte, a French engineer who has analyzed the painting, says he has discovered another portrait beneath the existing painting by using a technique called reflective light technology.

    He claims it shows an earlier image of a sitter looking to one side, which may be the original portrait of Lisa del Giocondo, who is also known as Lisa Gherardini — the woman who is thought to be the model for the “Mona Lisa.”

    But not everyone is convinced and the Louvre Museum, where the priceless painting is on public display, has declined to comment on the claims.

    As well as the mystery of Mona Lisa’s identity, there are theories that da Vinci painted more than one version and there are conflicting dates about when the painting was commissioned and finished.

    A new documentary called “Secrets of the Mona Lisa,” which aired at 9 p.m. yesterday on BBC, is aiming to shed light on some of these mysteries using new research and technology.

    Da Vinci is believed to have worked on the painting between 1503 and 1517 and for centuries, it has been believed the woman with the enigmatic smile is Lisa del Giocondo, the wife of a Florentine silk merchant.

    Presented by an art historian, Andrew Graham-Dixon, the new program will embark on an investigation using the latest optical, forensic and historical tools to examine new evidence that the painting hanging in the Louvre may not be the original Lisa.

    One of the techniques used is the Layer Amplification Method (LAM), which involves projecting a “series of intense lights” on a painting to reveal what lies beneath what is visible to the naked eye, the BBC reported.

    It was pioneered by Cotte, founder of Lumiere Technology, who in 2004 was granted access to scan the “Mona Lisa.”

    Cotte claims his technique is able to find layers undetected by other tests.

    In the latest findings from his study of da Vinci’s work, he said there are three different paintings beneath the Mona Lisa.

    One is claimed to be an early study of a head and another is a Madonna-style portrait with an extraordinary headdress.

    But the most surprising finding is the third “hidden portrait.”

    Cotte believes he has found the original portrait of Lisa del Giocondo — the Florentine merchant’s wife Mona Lisa, painted in 1503.

    He claims that this find finally resolves one of the Mona Lisa mysteries — that da Vinci painted more than one portrait of Mona Lisa and it lies underneath the one we all recognize in The Louvre.

    He says the earlier hidden image is da Vinci’s original portrait named Mona Lisa and it could be a different woman to the one we recognize in the painting in The Louvre.

    (SD-Agencies)