Image copyright AP Image caption The ring was bought by Temple's father in 1940

A diamond ring that belonged to former child star Shirley Temple is going up for auction next month at a starting price of $25m (£17.3m), Sotheby's says.

The auction house said the 9.54-carat "Fancy Deep Blue" ring was bought by Temple's father in 1940 for $7,210.

Temple, one of Hollywood's most popular stars in the 1930s, died in 2014 at the age of 85.

A private buyer bought the ring from her estate and is now putting it up for auction, Sotheby's said.

It is estimated to be worth up to $35 million.

Temple pursued a career in politics after leaving the entertainment industry, serving as US ambassador to Ghana and Czechoslovakia.

A selection of her belongings, including a dress worn at the 1935 Oscars, has previously been auctioned off by her family.

Image copyright AP Image caption Temple wore the ring as she was sworn in as a UN delegate in 1969