"She was a huge fashion icon so I would hope she would approve [of the timing]," said the starlet of her onscreen persona, 18th century British royal Georgina Cavendish.
To play the clotheshorse, Knightley endured two-and-a-half hour daily costume fittings on set.
"My ribs have just about recovered," said the actress of the heavy-duty corset she wore throughout, "but in the film you can see marks it left on my back."
Certainly, there were many in the fashion-heavy crowd at the after party at the new Cooper Square Hotel who could sympathize with suffering for the sake of style. Coco Rocha, for one, will be wearing a corset in the Zac Posen show tonight.
"It takes me about two hours to get into those," said the model, "once you factor in time for the smelling salts."
For the latest Fashion Week Eye coverage, click here.