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."