'Duchess' Keira Knightley to hold court during NY Fashion Week

Keira Knightley is one of the fashion world's favorite film actresses. And it's easy to understand why. No one wears haute couture so effortlessly, on and offscreen, as Knightley does.

Last year, Keira Knightley's exquisite "Atonement" costumes caused a sensation (ah, the slinky green dress in the sizzling library sex scene). And those Chanel and Rodarte couture gowns on the awards season red carpets made very haute fashion headlines.

This year, she's set to cause an even bigger style stir with "The Duchess," in which she plays 18th British celebrity/aristocrat/fashion icon, Georgiana Cavendish, the Duchess of Devonshire, who, like her French counterpart, Marie Antoinette, was both reviled and revered for her personal, political and fashionable excesses.

Trapped in a passionless union with the Duke (Ralph Fiennes) Georgiana falls in love with an ambitious young politician and well, we all know where that can lead.  Ironically, Georgiana is Princess Diana's direct ancestor.

Both girls were born at Althorp, pushed into the limelight by marriages to older, powerful and wealthy men, who both had public mistresses. No surprise that one of the film's taglines sounds like Diana's statement about her marriage to Prince Charles: "There were three people in her marriage."

"Duchess" promises to bring back memories of Princess Di and be a beautifully buttoned-up bodice-ripper.

And to spark interest among fashionistas, Paramount Vantage has teamed up with Fashion Week Daily to co-host an elegant party during the upcoming New York Mercedes-Benz Fashion Week.

The glam "Duchess" bash will take place in the Plaza's ostentatious Grand Ballroom on Sept. 9, the night before the film's New York premiere. (The movie opens Sept. 19.) This is the week that simply everyone who is anyone in fashion will be in town for the Spring '09 fashion shows of Calvin Klein, Phillip Lim, Michael Kors, Monique Lhuillier, Herve Leger, Matthew Williamson, Rodarte, Ralph Lauren, Donna Karan, Zac Possen, Vera Wang, etc.

Keira Knightley, Ralph Finnes, Charlotte Rampling, scads of stylish stars, famous designers and the international style press will sip champagne while checking out the film's costumes (by Michael O'Connor) on display.

We can hardly contain our enthusiasm. But we must. Decorum must be preserved. The Duchess would approve.

Or would she?

Photo: Knightley in "The Duchess." Credit: Courtesy of Paramount Vantage.