Avril Lavigne has filed for divorce from estranged husband Deryck Whibley.

The 'Girlfriend' singer took action to officially end her three-year marriage to the Sum 41 star at a Los Angeles court last Friday (09.10.09), citing "irreconcilable differences".

Avril Lavigne was reportedly seen flirting with another man in the lead up to her split from husband Deryck Whibley.

The 'Girlfriend' singer - who announced she was separating from the Sum 41 rocker last week - spent a month partying on oil heir Brandon Davis' yacht in St. Tropez, South of France, and sources say the pair have grown very close.

Paris Hilton was seen "grinding" with a new man at a nightclub. The 27-year-old socialite - who recently claimed she has been single since splitting with Good Charlotte rocker Benji Madden - was spotted getting close to MySpace CEO Chris DeWolfe at Tao at the Sundance Lift in Utah.

A source told the New York Daily News newspaper: "They were grinding each other on the dance floor forever, before lying together on a banquette. Then the couple began sucking face hard. They left out the back door, with her hand in his pants pocket."

Avril Lavigne's husband has warned Paris Hilton's ex-boyfriend to stay away from her. Rocker Deryck Whibley was reportedly furious after he discovered Avril had been out for dinner with oil heir Brandon Davis - who has also dated Lindsay Lohan - and texted his love rival saying: "Stay away from my wife."

However, a source is quoted by gossip blogger Perez Hilton as saying: "Avril assured Deryck that it was a business dinner about art, since Brandon also makes a living as an art broker. Deryck trusts his wife, it's just Brandon he doesn't trust."