Pablo Picasso was so taken with 17-year-old Marie-Therese Walter when he spotted her on a Paris street in 1927, he knew he had to paint her, declaring: “I'm Picasso – you and I are going to do great things together."

The collaboration between artist and muse – who met when he was 45 – led him to paint many pictures of her. But one – rarely exhibited ?and never in Australia – is about to bring the University of Sydney a windfall of up to $18 million when it is auctioned in London in June.

Prolific collaboration ... Jeune fille endormie was one of many paintings Picasso did of Marie-Therese Walter. He predicted they would do great things together. Credit:Greg Weight

The 1935 painting of a sleeping Walter, Jeune fille endormie, was given to the university by an overseas donor who had three conditions: that the painting be sold, that the money go to scientific research at the university, and that the donor remain strictly anonymous.

The university's vice-chancellor, Michael Spence, said the American donor had flown to Australia last year to hand over the painting. It had remained on the university's grounds most of the time since while checks were made on its provenance.