So that's how Ryan Phillippe stays looking so darn good! 

The sexy actor was spotted working out in Los Angeles on Thursday, and showed off his buff body in the process.

Sporting a white tank top, black basketball shorts and running shoes, the "Cruel Intentions" star looked like he was really working up a sweat. Perhaps the 39-year-old's trying to stay fit got his gorgeous girlfriend, Paulina Slagter. 

The cute couple have been together since 2011, and the blonde beauty is currently working on her law degree at Stanford University. 

Ryan must be doing something right -- he's looking happier and healthier than ever! 

How do you think the "I Know What You Did Last Summer" hottie looks? Sound off below and click "Launch Gallery" above to see even more sexy celebs! 

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