Spending time with Richie and Benji's brother also helped sway the star.
"Benji swept her off her feet," says a Diaz source.
"She found someone who knew how lucky he was to have her.
"Cameron hasn't been this happy in a long time," says a source close to the couple.
One of the highest-paid actresses (she pulls in more than a movie), Diaz has been at the top of her game for nearly two decades.
Fresh off filming Annie, "Cameron was more into music than ever before," says a friend of the couple.
She and the "Anthem" singer, who has sold more than 7 million albums with Good Charlotte, bonded over bands.
She just wants someone to share it all with." The Men of Cameron's Past slugger, 39, and Diaz called off their one-year romance in 2011, he called her "one of the greatest human beings I've ever met."Sean ' Diddy' Combs The 45-year-old hip-hop mogul still pines for Diaz, his on-off partner from 2008 to 2012.
A source tells Us the rapper is "bummed" she's now paired up with Benji!
The other guys treated her badly, but Benji would do anything for her.