Jessica Biel “Naturally” Bikini Butt & Ass on Puerto Rico beach

Clearly in fine form, Jessica is well known for being a dedicated gym bunny, and even she admits she is 'boring' as she keeps to a strict routine.

The actress is in Puerto Rico with her fiancé Justin Timberlake, 31, who's in town with the crew of his new movie, Runner, Runner.

To get a stunning physique like Jessica's does of course involve a lot of sacrifice the actress told ELLE magazine last year. She probably wouldn't be top of your list for a wild night out.

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Beach fit: Jessica Biel has no need to cover up as she showed off a very trim figure on the beach in Puerto Rico (Read more and See more Pictures)