Fight for Mel Gibson's fortune: After actor's frolic with brunette his wife of 28 years calls in lawyers

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. The Oscar-winning actor 53is 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 as the reason for the split. She also listed the separation date. 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.