BOSTON • It is the last known Leonardo da Vinci painting in private hands.
No wonder, then, that experts predict it will draw US$100 million (S$136 million) when it comes up for auction on Nov 15 in New York.
The auction of post-war and contemporary art will also feature a monumental work by Andy Warhol that could fetch US$50 million.
Da Vinci's Christ As Salvator Mundi dates back to around 1500. The small painting depicts Jesus Christ holding a crystal orb in his left hand and raising his right hand in benediction.
It is one of fewer than 20 paintings by the Italian Renaissance artist known to still exist.
"This is truly the Holy Grail of art rediscoveries," said Mr Alan Wintermute, Christie's senior specialist for Old Master paintings.
He added that the portrait, sometimes called the male Mona Lisa, had long been thought to have been lost or destroyed.
First recorded in the private collection of King Charles I, the work was auctioned in 1763 before vanishing until 1900, by which time Christ's face and hair had been painted over, which Mr Wintermute said was a "quite common" practice.
Sold at Sotheby's to an American collector in 1958, it was again sold in 2005 as an overpainted copy of the masterwork.
The new owner started the restoration process.
After about six years of research, it was authenticated as da Vinci's more-than-500-year-old masterpiece, which culminated in a high-profile exhibition at London's National Gallery in 2011.
The painting stands as the first discovery of a da Vinci painting since 1909.
The auction house did not identify the seller, a European private collector who acquired the work after its rediscovery in 2005 and lengthy restoration.
Being able to partner an Old Master painting with Warhol's work, called Sixty Last Suppers, appealed to the da Vinci seller, according to Christie's.
Warhol's 1986 work was inspired by da Vinci's famous The Last Supper.
Finished a year before the American pop artist's death, it depicts The Last Supper 60 times in black and white. The huge grid - 9.8m wide - has 10 columns and six rows.
Warhol got the idea for a group of works based on da Vinci's late-15th-century painting from Mr Alexander Iolas, a Milan-based art dealer, according to Christie's.
The artist made more than 100 different Last Supper works, some freehand, some showing outlines and others in silkscreen.
In 1986, 22 of these works were displayed in a space across from Milan's Santa Maria delle Grazie church, home of the original masterpiece, and viewed by 30,000 people.
The Warhol auction record belongs to Silver Car Crash (Double Disaster), a 1963 silkscreen painting that sold for US$105.4 million at Sotheby's in 2013.
The most expensive Last Supper at auction - a 1m by 1m canvas - went for US$18.7 million to British billionaire jeweller Laurence Graff.