LOS ANGELES (Reuters) - The wife of actor Mel Gibson filed for divorce on Monday after 28 years of marriage, citing irreconcilable differences.

In divorce papers filed in Los Angeles Superior Court on Monday, Robyn Gibson asked for her 1980 marriage to the "Lethal Weapon" actor to be ended, and in a joint statement the couple, who have seven children, sought privacy.

"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 statement said.

Late on Monday, the actor and director of movies including "Braveheart" and "The Passion of The Christ," filed a response saying the two had been separated since August 26, 2006.

Only weeks earlier, Gibson made worldwide headlines when he was arrested in Malibu for drunken driving and launched into an alcohol-fueled tirade against Jews that became public when the police report was leaked.

Gibson's response, which was posted on celebrity news website TMZ.com, also cites irreconcilable differences as the reason for the split.

Six of the Gibson's children are adults. Robyn Gibson asked for joint custody of the only minor, Tom, who turns 10 on Tuesday.

Gibson, 53, a staunch Catholic, was raised in Australia and was one of the highest paid and most popular actors in the world in the 1990s, winning a best director and best picture Oscars for his 1995 movie "Braveheart".

He has adopted a lower public profile since his controversial 2004 hit "The Passion of the Christ" and his 2006 arrest.

(Reporting by Jill Serjeant; Additional reporting by Bob Tourtellotte; Editing by Eric Walsh)