J.Lo's casual attire in Rome. Photo: Kika Press/Pacific Coast News

Jennifer Lopez may have celebrated her 40th birthday in high style, but the usually polished celeb's choice in wardrobe since arriving in Rome has been more tourist than A-list.

When Lopez, hubby Marc Anthony and their twins Emme and Maximilian touched down in Italy via private plane, the star was all glam in a tiered sundress and coordinating croc Birkin bag. She accessorized with a ton of luggage, of course!

But the actress-singer-designer did a complete fashion 180 when she hit the town in, of all things, (gasp!) sweats.

For a shopping trip with hubby Anthony on Rome's famous Via Dei Condotti, she traded her usual diva-worthy designer duds for a full-on frump fest: a disheveled white tee, baggy black sweatpants and gray sneakers. She topped off her look with a baseball cap.

While we're all for relaxing on vacation, J.Lo's gym style is a bit too casual for a woman famous for her Versace and who -- maybe not by choice, but by circumstance -- is representing the U.S., whether she likes it or not.

Plus, it wasn't like she was going the incognito route: Lopez was surrounded by bodyguards and even stopped to sign autographs.

What do you think? Should celebrities be held to style icon standards at all times? Or does anything go, especially while on vacation? Leave on comment with your opinion.