Mel and wife split after 30 years

Mel Gibson and his wife Robyn Moore, who have seven children together

Guy Adams in Los Angeles

It was supposed to be the happiest marriage in show business, lasting almost 30 years and producing seven children. But after months of speculation, Mel Gibson's wife started what could end up being one of Hollywood's most expensive divorces.

Robyn Moore filed for divorce in Los Angeles yesterday, citing "irreconcilable differences" for the breakdown in her relationship with the Oscar-winning star, whom she married in 1980. The Gibsons have seven children, but only one under 18. Robyn has requested joint-custody of their son Tom, who turns 10 today.

The couple, who now face a battle over Gibson's personal fortune, estimated at $900m, issued a joint statement making a somewhat ambitious request for privacy.

It was not clear how long the couple, who are both devout Catholics, have been separated, but a report by US TV show 'Entertainment Tonight' reported that they had been living apart for almost three years.

But Ms Moore's decision to formalise their separation may have been prompted by more immediate concerns: last month, newspapers published pictures of a topless Gibson (53) embracing a bikini-clad woman on the beach in Costa Rica.

Whatever prompted the move, it has come at an inconvenient time for Gibson, who is about to mount a comeback with the release this November of 'Edge of Darkness' -- his first major Hollywood title for almost five years.

His blockbuster career went seriously off the rails following his arrest for drink-driving in Malibu in 2006, when he launched an anti-Semitic tirade against the arresting officer.

"F***ing Jews ... Jews are responsible for all the wars in the world. Are you a Jew?" he was reported to have said.

The actor, whose mother comes from Co Longford, married Ms Moore, a 53-year-old former dental nurse in 1980, shortly after the release of 'Mad Max', the film which catapulted him to prominence. Almost all of his personal fortune was generated after the marriage, which was not governed by a pre-nuptial agreement. In her legal papers, Ms Moore seeks half of Mr Gibson's assets.