Congrats are in order for your favorite fit celeb! While Jessica Biel and Justin Timberlake have been engaged since late last year, she's been keeping her engagement bling a secret - until now. Yesterday Jessica Biel debuted her engagement ring while running errands in LA. The diamond's blindingly big size prompted our very own PopSugar to joke: is wearing that huge bauble around town its own arm workout? Maybe not, but Jessica does work hard for those toned arms (not to mention the rest of her body).