Jessica Biel perfects "Bikini" Butt & Ass on tennis game in Puerto Rico

Jessica paired the bikini with a long-sleeved purple-and-white surf rash vest and black sun visor.

Jessica, a former gymnast, has said she works had to maintain her killer physique.

Hiking, sprinting on a treadmill, yoga, swimming and working with a personal trainer are all in her regular routine.

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 Beach bodies: Justin went bare chested in a pair of board shorts, while Jessica showed off her exceptional behind in a tiny pair of black bikini bottoms (Read more, See more Pictures, and Watch Video)