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There's one part of Hilary's body that's getting bigger without a doubt - her muscles!

Hilary, carrying a spendy Goyard for a gym bag, hit the same gym we've seen Jessica Simpson and John Mayer working out at yesterday...but chances are she's just trying to get fit, NOT to fit into a wedding dress! And it looks like she's using protein powder to achieve her goals - check out that giant container in her trainer's hands!

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