One second, we're preparing to see them walk down the aisle. The next, it seems like their relationship is over! Famed Hollywood gossip Janet Charlton reports that Justin Timberlake has dumped Cameron Diaz. "Justin is poised to leave on a world tour and he wants to be free," says Charlton, who reveals that Timberlake and Diaz allegedly called it quits last week. Cammie D is said to be "devastated," though she looked happy as a stoner during her girl's weekend getaway to the Bahamas with Drew Barrymore. "Cameron is ready to settle down and wants a commitment, even though she might not admit it," says a source. "Justin is only 24 and he's been with Cameron for three years. He hasn't had a chance to sow his wild oats yet." The last string? Allegedly, Justin and his pals took off for a few days in Las Vegas recently and Cameron went chasing after him. How sad. Speaking of Timberlake, somebody should tell Mr. JT to get your ego in check! Sources tell PerezHilton.com that Justin was set to collect a lot of money to perform at the T-Mobile Sidekick 3 launch party in LA earlier this week, but once word got out - it was supposed to be a "surprise" - Timberlake backed out. Idiot! Update: PerezHilton.com has indeed confirmed that Justin and Cam are truly over! A source close to Timberlake tells us, "Homegirl [Cammeron] is blowing her lid, everyone [all of Justin's friends] knew what was gonna happen but her." Ouch!!!!