The auction house said the celebrated Austrian symbolist’s “Dame mit Facher” (Lady with a Fan) could go for some £65 million on June 27.

Described as a “beautiful, rich and alluring portrait of an unnamed woman”, the portrait was found on his easel in his studio when he died unexpectedly in February 1918 aged 55.

Helena Newman, from Sotheby’s, said it was painted during Klimt’s artistic prime, when he was producing some of his most famous and experimental works.

“Many of those works, certainly the portraits for which he is best known, were commissions,” said Newman, who is in charge of Sotheby’s Europe and global head of Impressionist and Modern Art.

“This, though, is something completely different – a technical tour de force, full of boundary-pushing experimentation, as well as a heartfelt ode to absolute beauty.”

The current highest price achieved at auction for any work of art in Europe is £65 million for Alberto Giacometti’s “Walking Man I”, sold at Sotheby’s in February 2010.

Claude Monet’s “Le bassin aux nympheas” went for £40.9 million at Christie’s in London in June 2008. Last March, Rene Magritte’s “L’empire des lumieres” sold for £59.4 million at Sotheby’s.

Klimt portraits rarely come onto the open market. Sotheby’s said the only other of the same standard – “Portrait of Adele Bloch-Bauer II” (1912) – sold for US$87.9 million at Christie’s in New York in 2006.

Two portraits are reported to have been sold privately for more than US$100 million each.

“Portrait of Adele Bloch-Bauer II”, which depicts the wife of a Jewish sugar industrialist, was one of them, and went for US$150 million in 2017.

The other, “Portrait of Adele Bloch-Bauer I”, sold for US$135 million in 2006 to the Neue Galerie in New York.