Picasso's portrait of lover Marie-Thérèse Walter is expected to fetch over £35m at auction

A rarely seen Picasso masterpiece has gone on show in London ahead of a sale where it is expected to fetch more than £35 million.

The artist painted the portrait of his lover Marie-Thérèse Walter in 1937, keeping it until his death in 1973 when it was bought by the current seller.

The portrait, Femme au Béret et à la Robe Quadrillée (1937), has been exhibited in public twice. It is on show at Sotheby’s in New Bond Street until the auction on Wednesday.

It will be sold alongside other Picasso works including a painting of a matador valued at £18 million and a portrait of his wife Jacqueline expected to fetch £7 million. Other lots includes pieces by Chagall and Van Gogh.

Helena Newman, chairman of Sotheby’s Europe, said the portrait, painted only months after his anti-war masterpiece Guernica, was a “defining portrait from a pivotal year in the oeuvre of the most globally recognised artist”.

She said she expected interest in it from around 100 “serious, active collectors” who could push the price well above the estimate.

Three years ago, Picasso’s 1955 painting Les Femmes d’Alger sold for £115 million at auction in New York.