(Lionel Cironneau, file/AP Photo)

Mel Gibson is not only single, but $425 million poorer, thanks to a divorce settlement finalized Friday between the actor and his wife of 31 years, Robyn Denise Moore.

The judgment, finalized by a judge in Los Angeles, keeps virtually all details of the settlement secret.  People magazine reports that the couple did not have a prenuptial agreement, meaning his ex-wife would be entitled to half of everything Gibson earned during their marriage.

The Oscar-winner's fortune has been estimated to be as high as $850 million, the magazine said, citing a 2006 report in the Los Angeles Business Journal.

Throughout the 31-year marriage, which produced seven children, Gibson directed, invested and starred in movies such as "The Passion of the Christ," which grossed more than $600 million alone.  He also invested heavily in real estate, including an island in Fiji he bought for $15 million in 2005.

People also reports that Moore, a former dental nurse, is entitled to half of any film residuals Gibson receives for the rest of his life.

Moore, 55, filed for divorce from Gibson, also 55, in 2009.  The two met in the late 1970s, when they were both tenants in a house in Adelaide, Australia.   Of their seven children only one, a 12-year-old son, is a minor and therefore subject to a custody agreement.

The divorce, which will take effect Jan. 9, is believed to be the biggest celebrity divorce payout in Hollywood history.  Director Steven Spielberg paid an estimated $100 million to Amy Irving in their 1989 divorce.

Gibson's divorce payout and the potential custody battle that lies ahead comes on the heels of the $750,000 he agreed to pay to Oksana Grigorieva, his former girlfriend and mother of his toddler daughter, Lucia, in August.

The two, who split last April, were engaged in a bitter custody dispute that included leaked recordings that sounded like Gibson engaged in a racist and sexist tirade, and Grigorieva accusing Gibson of domestic violence.

The "Braveheart" star pleaded no contest to a misdemeanor battery charge involving Grigorieva in March.  The Los Angeles County Sheriff's Department also investigated allegations of  attempted extortion by Grigorieva, but she was never charged.

Robyn Moore came to her now ex-husband's defense in the battery case, filing a brief declaration that Gibson had never physically abused her or their children.

The Associated Press contributed to this report.