An extremely rare full-length portrait by Gustav Klimpt has sold for about $39 million at a Sotheby’s auction in London. That far surpassed the Sotheby’s pre-sale estimate ranging from $19 million to $28 million.

The 1902 portrait of Gertrude Loew captures the 19-year-old daughter of Doctor Anton Loew, who was the director of a prominent sanatorium that treated luminaries such as Wittgenstein, Mahler – and Klimpt himself.

The work had never been offered on the open market – and was won by an unknown buyer.

The canvas is almost five feet high and was painted in an understated palette of lilac and creams.

It was being sold following a settlement between the heirs of Gertrude Loew and the Klimpt foundation.

“Portrait of Gertrude Loew” was the first major Klimpt work to sell at auction since the 1917-18 “Portrait of Ria Munk III” at Christie’s in 2010 – which amounted to about $28 million.