The music mogul and the actress were said to have dated between 20, and it's been claimed Diddy, 45, wishes he took their union further.
A source for Us Weekly claims to have overheard Diddy describing Cameron, 42, as the "sexiest girl in the world".
A source previously told Us she was set up with Madden by his brother's wife, Nicole Richie.
Diddy recently opened up about the one that got away, and it wasn't Jennifer Lopez.
"He was at dinner and the subject turned to Cameron (Diaz) dating Benji Madden," a source told Us Weekly.
"(Diddy) said, 'If I could turn back time, things would be different! After Diddy's Lopez days, he dated the 42-year-old "Sex Tape" star from 2008 to 2012.
“They are friends and are not dating,” the actress’s rep tells PEOPLE.
Diddy has dated plenty of gorgeous women over the years, but one in particular still has him reeling — Cameron Diaz.Cameron and Diddy are said to have met at the Oscars in 2008 and were spotted together on numerous occasion for several years afterward, during which they put on romantic displays, according to eyewitnesses.There are several reasons why I am better than Santa and the biggest one is that I really don’t care if you’ve been naughty or nice. Oh well the message remains the same so why bother changing it?Diddy joined their table around , and ordered bottles of booze for the table, where Diaz was dancing with her friends and drinking, too.According to a source, the table was packed and “Cameron and Diddy were very affectionate.” Still, a rep says the two, who left the club with their friends around a.m., are not an item.An insider tells Us Weekly that the rap mogul couldn't stop gushing over his former fling during a recent night out.