It's a style showdown between a silver-screen siren and a stunning supermodel!

Emmy Rossum flaunted her fit figure in this H&M Conscious Collection dress at an exclusive dinner celebrating the environmentally-friendly clothing line on Wednesday night in West Hollywood, Calif. 

She added a dazzling diamond statement necklace to spice up the classic LBD, rocking a pair of simple black sandals to finish off the look.

The "Shameless" actress isn't the only star who wore this beautiful black dress.

Miranda Kerr showed off her enviable bod in this look at H&M's Fall/Winter 2014-2015 show during Paris Fashion Week. The brunette beauty stole the spotlight in the front row, sitting with fashionable friends Jessica Alba and Solange Knowles.

Both women looked fantastic in the affordable frock, but we have to give the nod to Miranda. We love that her diamond choker lays perfectly on the neckline of the dress. Plus, the former Victoria's Secret model's classic up 'do is so chic! Emmy should have pulled her hair back to show off her bling.

But your vote is the one that counts -- who do you think wore it better? Tell toofab in the comment section below, and click "Launch Gallery" above to vote on more stars in dueling dresses.

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