Revealed exclusively to Confidential by Monk's Sydney agent Yoon Kim, the announcement ends months of speculation about the gradual deterioration of the high-profile couple's 18-month relationship.
"Sophie and Benji have officially split. The decision was mutual and they remain amicable," Kim's statement read. "This will be my only statement regarding this matter."
After meeting on the set of a Good Charlotte videoclip in mid- 2006, the starlet and the tattooed rocker embarked on a whirlwind romance which peaked with a marriage proposal six months later at Monk's Gold Coast home.
It was the perfect completion to Monk's fairytale move to Hollywood and helped mark her transition from fledging Aussie pop star to bona fide US celebrity.
Declaring she was "the happiest I've ever been", Monk and her man were in tune at the Australian MTV Awards in April when they arrived as a star quartet alongside Benji's twin brother Joel and his A-list partner Nicole Richie.
Yet by the end of 2007 there was more rock 'n' roll in the union. See how we broke the story here.
Madden did not accompany his fiancee to Oz and the obvious strain on their relationship is now believed to be the explanation behind Monk's botched AFI red carpet performance and 11th hour withdrawal from Channel 9's Carols by Candelight.
The confirmation comes two weeks after Confidential ran a photograph of the actress in LA without her engagement ring.
