A Leonardo Da Vinci masterpiece whose whereabouts has been a mystery since it sold in 2017 for a record $US450 million ($643 million) has turned up in an unlikely place, according to Artnet.com.

Leonardo da Vinci’s Salvator Mundi captured the world's attention when it sold for $US450 million in 2017. Credit:AP

Salvator Mundi is being kept on superyacht Serene owned by Saudi Crown Prince Mohammed Bin Salman, the publication reported Monday, citing two "principals involved in the transaction".

Another Saudi prince was said to have purchased the 500-year-old painting on the prince's behalf at a 2017 Christie's auction, the New York Times reported previously. Christie's declined to confirm that report.

The Saudi government's Centre for International Communication didn't immediately respond to a request for comment.