The next Brit thing

IT'S BEEN quite a summer for Dominic Cooper.

The 30-year-old London-born actor made a huge splash as Amanda Seyfried's fiance in "Mamma Mia!" and starting today he woos Keira Knightley in "The Duchess."

Cooper plays Charles Grey, Whig statesman in late-18th-century England who became British prime minister in 1830. Earl Grey tea is named for him. Georgiana, the duchess of Devonshire (Knightley), was a benefactor of Grey's and the celebrity lure to the Whigs, and the two carried on an affair that ended when the duke of Devonshire (Ralph Fiennes) threatened to cut the duchess off from her children.

The duke, of course, was carrying on his own affair at the time - in fact, his mistress lived with him and the duchess.

Cooper, at Toronto's Park Hyatt Hotel for the Toronto International Film Festival a few weeks back, said that he'd never known the story of the duchess before he read the script and didn't know "the idea of celebrity existed in the 18th century."

"It's incredible, isn't it?" he said.

"I loved the script," he said, acknowledging, "it has some wonderful speeches in it - political speeches . . . and anything more than two lines long [in a script] is quite nice. And Grey was a fantastic orator and speechwriter."

Cooper did a great deal of research on Grey and the workings of British Parliament and came to think of him as a fierce politician who was charming and cocky (politicians haven't changed at all in 200 years) but whose love for Georgiana, even though he used her to further his career, was sincere.

"What I kind of adored about Grey," he said, "is that he knew exactly what he wanted and where he wanted to go, and was still willing to give everything up for the woman he loved."

Not that pursuing Georgiana was necessarily a wise plan. "To think that a woman would leave her children for him was either extremely arrogant or just stupid," Cooper added.

"Mamma Mia!" allowed Cooper to dance around in his swim trunks ("Singing in a bathing suit is something I never thought I'd do," he said), but "The Duchess" trusses him up in the layers of knickers and shirts and jackets of the day.

"The moment you step into the costumes," he said, "is when you really get a feeling of what these people felt like physically. . . . I have no idea how they went to the toilet."

As for romance: "It's difficult to whisper in the ear of a woman wearing something so vast."

Costuming was so time-consuming, Cooper said, that the costume department covered the actors in plastic sheets during lunch.

One of the interesting footnotes to "The Duchess" is that Georgiana, who was sort of the Princess Diana of her day due to her celebrity, popularity and fashion sense, is an ancestor of Diana's in the Spencer line. And as Georgiana's emotionally constipated husband, Fiennes has drawn comparisons to Prince Charles.

"It's such a clever performance," Cooper said of his co-star. "He turns a really unlikable man into someone you almost feel sorry for."

After "The Duchess," Cooper has two more films to be released - "An Education," by writer Nick Hornby, and "Brief Interviews with Hideous Men," adapted from the short stories by the late David Foster Wallace.

But now he's going to have to make some choices. Does he try for a role in a big Hollywood film or do something small and gritty? "I've been so lucky and so busy," he said, "but I do have to make some decisions."

One decision Cooper hopes will be made for him pertains to Britain's National Theater. If all goes well, he hopes to star next year in a production of "Phaedra," opposite Helen Mirren. *