Pitt and Aniston married in July 2000

The couple, who married in a lavish ceremony in July 2000, have not spoken publicly about their decision to split.

A petition filed at Los Angeles Superior Court seeks dissolution of the actors' marriage based on irreconcilable differences.

Aniston, 36, has been promoting her latest film, The Breakup, in the US.

Despite the film's title, the Friends star has declined to discuss her private life.

But talking to US TV show Access Hollywood about press coverage of the couple's separation, she said: "There is always going to be the tough and the nasty. You just tune out to that."

Aniston and Pitt remain partners in production firm Plan B, whose first film, Charlie and The Chocolate Factory, is due out later this year.