Because it is the same couture dressthe actorwore in a 2004 commercial for the Chanel No.

With its drop-waist and just-this-side-of-scandalous center slit, the dress has a mermaid-like shape.

Nicole Kidman

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Nicole Kidman

John Shearer

Nicole Kidman

Noam Galai/GA/Getty Images

Nicole Kidman

WWD/Getty Images