Spot the difference: Cameron on a US TV show (left) and at a London photocall (right). Photos:GettyImages/AP
We've hardly been able to keep track of J Brand 'Major' jeans, black top and black pointed courts combo - and that's because she'd already worn the very same outfit during the London leg of her campaign tour. She even accessorised with identical hair and similar golden bracelets.
Cameron clearly didn't seem worried about wearing the same thing twice - the stretchy jeans enabled her to throw some, err, questionable shapes, and show programme host Jimmy Fallon some serious love...
Bad Teacher: Cameron teaches host Jimmy Fallon her best moves, and greets him with a warm hug. Photos:GettyImages
Ms Diaz is the latest in a line of famous faces to work 'recycled style', following in the footsteps of Samantha Cameron and Duchess Kate, who've both been spotted re-wearing favourite frocks.
We're really hoping this is a style-savvy trend more celebs chose to follow, but what do you think of Cameron's re-run?
Look back at Cameron's beauty evolution by clicking on our gallery below:
Beauty Evolution - Cameron Diaz
Hollywood's golden girl is known for her box office hits and megastar boyfriends, but can we talk about her ever-changing hair and makeup? Take a look at the many faces of Cameron Diaz, then and now!
Beauty Evolution - Cameron Diaz
We first met the star in 1994 when she starred alongside Jim Carrey in The Mask. She was young, fresh-faced, and absolutely stunning. And her lilac eyeshadow looks so gorgeous on her blue eyes, we'll forgive her for the too-light foundation.
Beauty Evolution - Cameron Diaz
Hey, isn't that Shanna Moakler (former Mrs. Travis Barker)? No, it's Cameron at the 1st Annual Blockbuster Entertainment Awards in 1995. We're so glad she gave up the roots and fake hair (but kind of intrigued by this rare view of her natural colour!).
Beauty Evolution - Cameron Diaz
Cameron sported a layered cut and brick-red lips to a convention in 1996, the year she starred with Keanu Reaves in Feeling Minnesota.
Beauty Evolution - Cameron Diaz
We love the "no makeup" look and super-cute haircut Cameron had at the In & Out premiere in 1997.
Beauty Evolution - Cameron Diaz
Witness the Something About Mary cut in its full glory, at a press event in 1998.
Beauty Evolution - Cameron Diaz
By the time There's Something About Mary premiered in July, Cameron had finally broken up her too-blunt cut into layers. Again, we love the lilac eyeshadow on those baby blues!
Beauty Evolution - Cameron Diaz
Cameron looked ethereal at the Shrine Auditorium in 2000, the year the first Charlie's Angels movie came out. Her barely-there brows, black dress, and pale skin made her look too washed out. But still stunning!
Beauty Evolution - Cameron Diaz
We love Cameron's funky waves at the MTV Movie Awards in 2000. However, the cool platinum hue is a bit extreme, so we're glad to know that Cam goes more golden in the future.
Beauty Evolution - Cameron Diaz
At the 2001 MTV Movie Awards, Cameron looked disheveled. The berry lips lacked definition (lip liner...stat!), the brown shadow was dull, and the hair didn't help, either.