Because just like her brand-expanding pal before her, the actress is dipping her toes in the publishing world, as E! News has exclusively learned that the thesp is busy writing her first book!
So, what's the tome all about?
Far from being a celebrity vanity project, the What to Expect When You're Expecting star is putting pen to paper for a very good cause, and is writing a book about the importance of proper nutrition and staying healthy for impressionable young girls.
"She wants to stop their fixation on being thin, and for teenage girls to understand that being healthy is more important," a publishing source told E! News. "She wants to use her celebrity to make a difference. She knows she is a role model to girls and she really wants to use that position to do good.
"This book is not about weight, it's about making the right choices."
No formal publishing deal is yet in place, but Diaz has been mulling over the idea for some time, and has signed on with a literary agent.
And lest you think Diaz is simply lending her name to the noble endeavor and nothing more, think again.
"Cameron is going to be visiting high schools around the country to talk to teenagers about their food choices and what is important to them," the source told E! News. "She wants them to know that being thin should not be their priority, it's about getting the right vitamins and knowing what foods will give them energy and keep them strong. She wants to get their feedback, learn about how they decide what to eat now, and teach them to make more informed choices."
In other words, put the legwork in. So, how and when did the literary urge strike Cameron's fancy?
"Everything changed for Cameron after her father died," the source said. "She realized what is important and started to think more and more about her health."
Her good intentions, coupled with her unprecedented access to the top nutritionists in the world, has resulted in Diaz's desire to pass on the lessons she's learned to young women.
But there is one thing the book will not be.
"This book isn't about her. And it's not a diet of any kind. Of course, it's her own journey that has helped her realize what's important, but she wants the book to appeal to everyone, and not just be about her own food choices."
In addition to her own story, the book will also feature advice and expertise not only from top nutritionists, but some of Cameron's celebrity pals, including Drew Barrymore, Jennifer Lopez and, yes, Gwyneth Paltrow, who, it turns out, has been a bit of an inspiration to her fellow movie star.
"Cameron has become very close to Gwyneth and it's been very interesting for her to see what Gwyneth is doing with Goop," the source said. "She's been inspired by Gwyneth and the way she uses her fame to influence and help people. Now Cameron wants to do the same."
Diaz's rep confirmed the actress' interest in the project, saying "This is one of many projects she is considering for the future but nothing firm or ready to announce."
Though she has yet to sign on any dotted lines, a book deal seems inevitable, and could be ready as early as next year. When it does finally hit shelves, Diaz will also launch an accompanying website to further educate young girls on health issues.
And that might just be the beginning.
"Through this project, she wants schools to offer better meal options for kids," the publishing source continued. "She wants to have an impact on a huge scale. In some way, she feels like this is her calling. This is her passion."
—Reporting by Marc Malkin