A previously unseen painting by Marc Chagall is to go on display after it was acquired by a small London gallery.
The Ben Uri London Jewish Museum of Art bought the work, titled Apocalypse in Lilac, Capriccio, for a bargain £26,000 at an auction in Paris last year.
The gallery bought the work in a secret operation designed to avoid alerting the world's big galleries to the existence of the painting.
It will be unveiled at the Osborne Samuel gallery, in Mayfair, on Friday.
The 1945 work is one of only 10 by Chagall, created between 1938 and 1945, to feature a Jewish Christ.
David Glasser, from the Ben Uri London Jewish Museum of Art, spotted it fully catalogued in a Paris sale brochure, and recognised it "as a missing piece of Chagall's wartime imagery".
He said they paid a tenth of what they were prepared to pay for the painting after securing money from The Art Fund.
Mr Glasser said the painting was simply placed in the "wrong sale in the wrong country" keeping the price low.
Had it been placed in a sale in New York or London then "the world's eyes would have been on it," he added.
"This previously unknown work is Chagall's deeply personal expression of horror and mourning for the Jewish civilisation almost wiped out by the Nazis alongside and merged with grief for his late wife Bella who died eight months earlier," Mr Glasser said.
"The Art Institute of Chicago, The Musee d'Arte Moderne, Paris, The Israel Museum and now Ben Uri in London are the four museums across the world that are custodians of this hugely important but tiny body of work where Chagall employs a Jewish Christ between 1938 and 1945."
Apocalypse in Lilac, Capriccio, will be included in a long planned exhibition of 50 works from the collection at the Osborne Samuel gallery.
It will launch Ben Uri London Jewish Museum of Art's campaign to find and fund a larger permanent gallery in central London.