A court has ordered a woman to give her lottery jackpot of $1.3m (£800,000) to her former husband because she kept it secret during their divorce.

The California state lottery commission confirmed that Denise Rossi won the money on December 28 1996 - 11 days before she filed for divorce from Thomas Rossi after 25 years of marriage.

The superior court judge, Richard Denner, said Ms Rossi violated state disclosure laws and acted out of fraud or malice. In court papers, she admitted to concealing her winnings because she didn't want her former husband "getting his hands on them".

Mr Rossi found out about the winnings more than two years after his divorce when he received a mailed solicitation from a company that pays lump sums for lottery winnings.

The letter, addressed to his wife, said that the company had "helped hundreds of lottery winners like you around the country receive a lump-sum payment for the present value of their future annual lottery payments".

"I think he scratched his head for a while, saying: 'What? This can't be,'" said Mr Rossi's attorney, Mark Lerner. Mr Rossi obtained a court injunction a few days later.

As part of the ruling, Ms Rossi must pay her ex-husband 20 annual installments of $66,800. Her attorney, Connolly Oyler, called the judge's ruling "very punitive" and said his client would appeal.

She and five co-workers in a clothing design firm pooled their money to play the lottery and shared $6.6m, she said.

Mr Oyler said he might have had a chance during the divorce to help Ms Rossi keep the winnings if she had told him about them.

"I could have argued successfully that it was her separate property," he said. "Or we could have argued and we would have reached some adjustment. But the judge got mad and gave it all to him."