|The Earlier Mona Lisa depicts a woman in her 20s, so says the caption.|
16 December 2014 Last updated at 05:13 ET
A portrait of a younger Mona Lisa, which its owners claim was painted by Leonardo Da Vinci before his more famous version, has gone on display.
The painting is being exhibited in public for the first time in Singapore.
Its owners say expert tests and analysis confirm Da Vinci painted it 10 years before the better-known version.
But its authenticity is disputed. Da Vinci expert Martin Kemp said it was "just another copy of the Mona Lisa, an unfinished one, and no more than that".
Prof Kemp, emeritus professor of the history of art at Oxford University and the author of several books on Da Vinci, said: "The fact it's being shown in Singapore and is not getting an outing in a serious art museum [or] gallery is significant in itself.
The painting, he said, was "routine in handling". He continued: "Leonardo's landscapes always seethed with a sense of life. It's inert.
"The drapery is inert, and what Leonardo did was he could always give the sense that even something static like drapery had a life to it, a vitality and an inherent movement in it, and this is a heavy-handed, static picture."
But the Switzerland-based Mona Lisa Foundation, which manages the painting, says historical evidence, other expert opinions and carbon dating and further scientific tests point to its authenticity.
"We feel these latest discoveries and new scientific analysis just carried out leave little doubt that it is Leonardo's work," auctioneer and Mona Lisa Foundation vice-president David Feldman told the Reuters news agency.
"The vast majority of experts now either agree with us or accept that there is a strong case for our thesis."
The foundation says Da Vinci created the work in 1503, 10 years ahead of the Mona Lisa, but left it unfinished.
It was later acquired by an English aristocrat in the late 1770s.
The earlier Mona Lisa was discovered in 1913 by an art collector while visiting a British aristocrat in Somerset.
Taking it back to his studio in Isleworth, south west London, for restoration, it was the dubbed the Isleworth Mona Lisa for its close resemblance to Da Vinci's most famous painting, which hangs in The Louvre gallery in Paris.
The artwork will be on show until February at the Arts House in Singapore's Old Chambers of Parliament, before touring Hong Kong, China, South Korea and Australia.