Here, Zac Posen walks EW through major details about his masterpiece.

Posen set out to create a gown that highlighted the place where technology and fantasy meet.

I think fashion has become something called fashiontainment, reflects Posen.

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Credit: Taylor Hill/FilmMagic

And its our job as dreamers and creators to push that.

And while Danes may have sparkled like Cinderella, she also shared the princess midnight curfew.

Not that Danes, husband Hugh Dancy, or Posen stayed out extraordinarily late.

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Taylor Hill/FilmMagic

Shares Posen, I dropped Hugh and Claire off and then I was in bed asleep by 2:30.