The gorgeous face of Keira Knightley holds the center of virtually every frame of the sumptuous new period piece "The Duchess." But beneath the perfect makeup, the towering beehives, flouncy hats or deliciously back-lit mounds of curls, the camera captures much more than her supermodel looks. There's love, fear, expectation, disappointment, betrayal, lust and intelligence behind those eyes.

She doesn't just wear the clothes, and wear them better than anybody. The lady can act.

As Georgiana, the real-life Duchess of Devonshire, Knightley brings to vivid life a woman very much of her time, even as she was ahead of it. Popular, fun, a great wit and smarter than her unfaithful, boring and boorish husband, some see her as an 18th-century version of Diana, Princess of Wales.

"The Duke of Devonshire must be the only man in England not in love with his wife," one character gossips. That sounds awfully familiar to anyone who can connect the names Charles, Diana and Camilla.

But behind setting the fashion trends, supporting the liberal Whigs against the conservative, anti-American Independence Tories, the gambling and the fun, Georgiana suffered in a loveless marriage to a rich and powerful man very much of his time, a husband who treated their union as a contract, one she wasn't fulfilling if she didn't provide him with a male heir.

Ralph Fiennes plays the Duke close to his 18th-century vest. He's not a beast. But he acts as his station in life and the age he lived in allowed him to act, with impunity.

And as she wowed the crowds and played at politics, he took a tumble for her best friend (Hayley Atwell of "Brideshead Revisited") and forced Georgiana into an arrangement that had to remind her, every day, of a woman's place in that society — as property, so wholly without rights that a husband could beat her with a stick, just so long as that stick "is smaller than his thumb."

Saul Bibb's gorgeously detailed film captures much of the milieu, the by now over-familiar resort at Bath, a location for every Austen-era Brit film of the past 20 years. Characters such as future Prime Minister Charles Grey (Dominic Cooper of "Mamma Mia!") and the playwright Richard Sheridan (Aidan McArdle), whose "School for Scandal" was inspired by the Duke and Duchess, were part of their circle.

We see the lush drawing rooms in what resembles natural light, the raucous political dinners of the day glowing with candles. We see the confining clothes so symbolic of that confining era, down to the marks her corset leaves on Georgiana's back.

If you're looking for justice, some form of righteous relief for this woman, "The Duchess" can be a frustrating experience. Searching for deeper meaning and purpose to her life can be as pointless as trying to find that in the sad story of Diana Spencer. Both were born rich, married royalty and died richer.

But there's enormous pleasure in watching Knightley mature into the movie star she has become, an actress hiding the spunky spitfire that made her, in service of a grand, old-fashioned tragic romance. If "Atonement" let the woman leave her girl behind, "The Duchess" allows the woman to take her screen persona to a new level — regal.