THE PAINTING WHICH triggered the end of Pablo Picasso’s first marriage will go under the hammer at Sotheby’s in London next week.

La Lecture depicts the artist’s muse and mistress at the time of painting: Marie-Therese Walter.

Picasso and Walter’s relationship was kept secret for years because of the difference in their ages – and because he was already married. Walter was just 17 when she stepped off a Paris train and was approached by Picasso, then 45 years old. She didn’t know who he was, but he told her: “I am Picasso – you and I are going to do great things together.”

Walter appeared in other paintings by Picasso before La Lecture – however she had always been disguised, the BBC reports.

When the painting of Walter was exhibited, Picasso’s wife Olga Khokhlova realised that the painter was involved with another woman and subsequently called an end to their marriage.

Walter and Picasso later had a daughter, Maya.

La Lecture, painted in 1932, is expected to fetch between £12m and £18m, according to the Independent.