Actor Robert Downey Jr. married his girlfriend, Susan Levin, a movie producer he met on the set of the film Gothika, on Saturday, People magazine reported.

Downey, who has starred in more than 50 films, including Less Than Zero, Chaplin and Wonder Boys, has the reputation of being a talented but troubled actor.

The guest list at the we-dding on Long Island, New York, included actor Keanu Reeves and musicians Sting and Billy Joel.

Downey, 40, and Levin, 31, met in 2002 and were engaged in November 2003 when The actor presented her with an engagement ring of diamonds and a rare African sapphire, the magazine said.

Downey stars as a petty thief caught up in a Los Angeles murder investigation in the Warner Bros comedy thriller Kiss Kiss, Bang Bang, set to open in September.

Downey struggled with drug addiction during the 1990s and had several run-ins with the law.

For six years, the award-winning actor was in and out of prison and rehabilitation programmes after police found heroin, crack and an unloaded gun in his car.

In 1999, he served a year in prison for cocaine possession and was arrested twice for the same offence within months of his release.

The fallout from those incidents cut short a budding comeback for the actor, who won Golden Globe and Screen Actors Guild awards for his role in the TV series Ally McBeal. (Reuters)