
Mel Gibson’s wife of 28 years has filed for divorce, setting the stage for one of the most expensive marriage break-ups in legal history.
Under Californian law, Robyn Gibson could take half of her husband’s £640million fortune.
She lodged papers in Los Angeles Superior Court weeks after Gibson was pictured frolicking on a beach in Costa Rica with an unidentified brunette.
The Oscar-winning actor, 53, is said to have become close to a Russian brunette on the set of his most recent film, but denies he has had an affair with the woman, a musician known simply as Oksana.
The court papers filed by 52-year-old Mrs Gibson cited ‘irreconcilable differences’ as the reason for the split.
She also listed the separation date as ‘to be determined’, while Gibson named August 26 2006 – a month after his controversial drink driving arrest – as the date in his divorce petition.
The couple released a joint statement last night: ‘Throughout our marriage and separation we have always strived to maintain the privacy and integrity of our family and will continue to do so.’
The couple have seven children, six of whom are grown up. Mrs Gibson is seeking joint custody of the youngest, Tom, who is ten this week.
The former nurse and Gibson are not understood to have a prenuptial agreement.

Despite the irreconcilable differences cited by Mrs Gibson, many in Hollywood believe the real reason behind the split is her husband’s close relationship with Oksana.
She is one of the artists on the Australian-born actor’s recording label Icon and has been in the U.S. recording an album.
Gibson denies that she is anything more than a colleague, but the pair have been snapped coming out of his trailer on the set of The Edge of Darkness, which is due for release this year.
Gibson, a staunch Roman Catholic, was one of the highest-paid and most popular actors in the world in the 1990s, winning best director and best picture Oscars for his 1995 film Braveheart.
He has adopted a lower public profile since his controversial 2004 hit movie The Passion of the Christ and his 2006 arrest for drink-driving in Malibu, when he launched into an alcohol-fuelled tirade against Jews.

Not long before his arrest he was photographed partying with female admirers.
‘The incident definitely took a toll on his marriage,’ an acquaintance of the actor told the Daily Mail last night.
‘Robyn was humiliated by the fallout from that incident, as was his entire family. Mel never thought there was anything inappropriate about his relationships with other women.
‘In his mind, it was perfectly natural to have female friends – even if they were beautiful and often far younger than him. It was something his wife needed to deal with as far as he was concerned.’
Mrs Gibson is being represented in the divorce by the lawyer Laura Wasser, whose previous clients include Britney Spears, Angelina Jolie and Keifer Sutherland.
An almighty fight is now on the cards over what is perhaps the largest fortune of any Hollywood actor.
Gibson was ranked No 1 on the Forbes celebrity rich list in 2004 and has his own film production company.

The family: Gibson with his wife Robyn in 1999 and their children (back row) William, Hannah and Christian, (front row) Christian’s twin Milo, and Louis; Tom was yet to be born
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