Demi Moore was first to give this dress its designer debut, wearing it to the Rodeo Drive Walk of Style Awards in LA, way back in September last year.
The actress teamed the draping LBD - which is from Zac Posen's Spring/Summer 2010 collection - with her enviably glossy mane, matching black peep-toes, elegant silver bracelets and a black satin clutch.
Next up, and Kate Beckinsale followed in Demi's oh-so-fashionable footsteps, by sporting the very same frock to the Hot List party in Las Vegas this week.
Demi Moore and Kate Beckinsale in Zac Posen - Who wore it best? - Marie Claire" title="Demi Moore and Kate Beckinsale in Zac Posen - Who wore it best? - Marie Claire"/>
The Brit actress teamed her halterneck with some high-volume curls, a chunky gold statement ring, black clutch and two-tone Christian Louboutin Luly heels.
So, two brunette beauties, one designer dress - and the million dollar question. Who wore it best? Let us know who gets your vote in the comments box below!