She's the one that got away! Diddy has dated plenty of gorgeous women over the years, but one in particular still has him reeling — Cameron Diaz. An insider tells Us Weekly that the rap mogul couldn't stop gushing over his former fling during a recent night out.

"He was at a dinner and the subject turned to Cameron dating Benji Madden," the source tells Us. "He said, 'If I could turn back time, things would be different!'" (Diaz began dating the Good Charlotte rocker in May.)

The insider adds: "He was bummed, saying, 'She's the sexiest girl in the world.'"

Diddy, 45, who previously dated Jennifer Lopez for three years, first hooked up with Diaz, 42, back in 2008. In 2012, the Annie actress was spotted straddling Diddy at a CAA gala in West Hollywood. "Her hair was all crazy, her makeup was smeared and they made out in front of everyone," an onlooker told Us at the time. "She was acting like a teenager!"

Alas, the romance never really blossomed, and Diaz — whose exes include Justin Timberlake, Jared Leto, and Matt Dillon — moved on. A source previously told Us she was set up with Madden by his brother's wife, Nicole Richie.

For more of the hottest news, watch this week's Hot Stuff video, hosted by Us Weekly Entertainment Editor Ian Drew and singer and singer and Redneck Island cohost Jessie James Decker.

Also in the roundup: awkward Scandal sex scenes on set, Miley Cyrus and Patrick Schwarzenegger's new romance, and more!