The last privately owned Leonardo da Vinci painting and one of fewer than 20 by the Renaissance artist known to still exist is hitting the auction block, Christie's announced on Tuesday.

"Salvator Mundi," an ethereal portrait of Jesus Christ that dates to about 1500, is expected to sell for about $100 million at Christie's in November, making it among the most highly valued works ever to be sold at auction.

"This is truly the Holy Grail of art rediscoveries," said Alan Wintermute, Christie's senior specialist for Old Master paintings, explaining that the portrait sometimes called the male Mona Lisa had long been thought to have been lost or destroyed.