Wallace Simpson's Cartier tigers to go under the hammer

Soprano Sarah Brightman is hoping to raise £1.5 million when she auctions two pieces of Cartier tiger jewellery given to her by her ex-husband, Andrew Lloyd Webber.

Cartier's Tiger jewellery designs first appeared in 1928, alongside the company's already-celebrated panther range. This particular onyx and diamond clip brooch and bracelet, with emerald eyes, were both made in the 1950s.

Set to go on sale as one lot on November 11 through auction house Christies, they were formerly owned by Wallis Simpson, the Duchess of Windsor. They were a present from husband Edward VIII some time between 1956 and 1959, a decade after he abdicated to marry the twice-divorced American.

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Valuable collection

The duchess loved fine jewellery, and, thanks to Edward, built up an enormous and highly-valuable collection of avant-garde designs. The collection was sold in Geneva after her death in 1987 in the world's most valuable ever auction of jewellery. Seven Great Cats pieces were included: and Lloyd Webber snapped the bracelet and brooch up as a present for Brightman to celebrate the success of The Phantom of the Opera, which he wrote and in which she starred.

"The rarity of these pieces is enhanced by the story behind their ownership – two romantic tales where they became symbols of love through the act of giving," says Christies. "Over the years, the jewels have brought immense joy to Ms Brightman, who would now like to release them to new splendour in order for others to appreciate them as she did."

Brightman says she plans to give part of the proceeds from the sale to the Andrew Lloyd Webber Foundation, which supports the arts, music in schools and the Architectural Heritage Fund, and which awards performing arts scholarships.

Value depend on how often items were used

It's hard to say exactly how much the celebrity connection adds to the value of the pieces - such extravagant Cartier items command sky-high prices anyway. But research last year from the University of Michigan found that the amount collectors are prepared to pay for a celebrity item depends on the degree to which it was touched and used by the star.

The reason, say the researchers, is 'magical thinking' - the belief that the buyer will in some way be able to share in the celebrity's character or life. Whether the buyer of the Cartier pieces next month will be channelling Brightman or Simpson, we'll probably never know.

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