The painting, titled Portrait of Fraulein Lieser, is one of the last works by the world-renowned artist.

The painting was considered lost for about 100 years - until it resurfaced in the private collection of an Austrian.

According to Austrian media reports, the artwork was last seen in public in 1925 and was previously only known to experts through a black and white photograph.

Its whereabouts had remained a mystery since then - until it was discovered on the wall of a family villa near Vienna.

The painting once belonged to the Lieser family, who were wealthy Jewish industrialists in Vienna.

The Viennese auction house Im Kinsky estimates the painting's value at more than €50m (£42m).

"The rediscovery of this portrait, one of the most beautiful of Klimt's last creative period, is a sensation," it said.

"His work, particularly his portraits of successful women from the upper middle class at the turn of the century, enjoy the highest recognition worldwide.

"A painting of such rarity, artistic significance, and value has not been available on the art market in Central Europe for decades."

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The painting is to be sold at auction on 24 April, before which it will be showcased worldwide, going on display at various locations including planned stops in Britain, Switzerland, Germany, and Hong Kong.

Klimt's Lady with a Fan sold for £85.3m at Sotheby's in London in June - setting a new record for any work of art sold at auction in Europe.