Jen Aniston Rolls Around in Bed Topless, Flashes Abs in Sexy New Ads

Jen's ripped -- and sweaty!

In a new print advertisement for SmartWater, Jennifer Aniston -- drenched in sweat -- shows off her impressively toned abs.

Wearing workout gear and clutching a bottle of water, the fit 41-year-old gives the camera a breathless look.

"Working out feels great...afterwards," the copy below reads. "That's why I drink Smart. It's hydration I can feel. (And it's one part of my routine I never sweat.)"

Yoga and fitness buff Aniston has been a spokeswoman for Glaceau SmartWater since 2007. Soon after the star signed on, a SmartWater executive said, "Jennifer truly embodies what smartwater is all about as she combines substance and style."

Aniston's newest business venture: Lolavie, her first fragrance, announced last month.