Stone and Bronstein married on Valentine's Day 1998

The couple - who are requesting joint custody of their adopted three-year-old son, Roan - said in a statement they are parting on friendly terms.

"We're committed to being great parents and having a friendship, as parents, moving forward," the statement said.

"We intend to keep our son's happiness as our foremost priority and thank you for allowing us to keep this a private family matter."

Stone, 45, and Bronstein, 52, married on 14 February, 1998.

"There will be no drama here. They both have the interests of their three-year-old at heart and are trying to resolve this in a very private manner," Bronstein's lawyer Nordin Blacker said.

"They are trying to achieve an amicable and mutual dissolution of their marriage and are committed to being parents of their child and to doing this in as friendly and non-controversial a manner as possible."

Bronstein, who is executive editor of the San Francisco Chronicle, indicated in papers filed at California Superior Court that a financial settlement would be negotiated separately.

Rumours

Rumours about the marriage had been circulating around Hollywood for some months, and on Thursday the New York Post reported the couple were already living apart, with Stone moving to Los Angeles.

The paper claimed the pair split after she returned from making her latest film, A Different Loyalty, in London and Moscow.

Stone shot into the spotlight thanks to the 1992 sexual thriller Basic Instinct, in which she played a killer suspected of luring her prey by seducing them.

But since then her career has cooled, and in 2001 she suffered a stroke.

She said afterwards she almost died after internal bleeding caused by a tear in an artery at the base of her skull.

In the same year, Bronstein was attacked by a Komodo dragon during a visit to Los Angeles zoo, and needed emergency surgery on his toe.

Stone has been married once before, to film producer Michael Greenberg. That partnership ended in 1997.