Justin Timberlake and Jessica Biel apparently have to work at being the most toned couple in Hollywood.

Dressed in his 'n' hers Nike sportswear, the pair worked up a sweat as they  jogged along the Chelsea Piers in Downtown Manhattan yesterday.

And by the looks of Justin's strained face, it seems the Sexy Back star has a little ways to go before catching up with his super-fit girlfriend, who seemed to be taking their running session in her stride.

Jess is currently showing off her fabulous body in straight-to-DVD stripper romp, Powder Blue.

See her in action below (warning: NSFW):