A portrait of Pablo Picasso’s mistress, Dora Maar, was put on public display on Wednesday for the first time in 40 years. The painting is due to be auctioned in New York on May 3. Up until now, It has been in private hands. The portrait is estimated to sell for $50m, (£29m).

Picasso’s portraits of Maar, a photographer who was his muse and companion for almost a decade, are regarded as being among the artist’s most important. The painting, “Dora Maar au chat”, shows Maar seated in a chair with a small black cat perched behind her right shoulder.