Jennifer Aniston has formally called off her four-and-half-year marriage with actor Brad Pitt by filing for divorce citing "irreconcilable differences".

Hollywood's former golden couple, who married July 29, 2000, and have no children, had issued a joint statement in January saying they were formally separating, reported ABC News.

While speculation is rife that it was the former "Friends" beauty's reluctance to start a family that had caused the rift, there were rumours that "Ocean's Twelve" star Brad had an affair with his "Mr and Mrs Smith" co-star, Angelina Jolie - something which both have denied.

There were also rumours that Brad and Jennifer could get back together with some sources claiming they were seeing a counsellor in a bid to save their marriage.