American men are vain, says Knightley – though Johnny Depp's not a bad kisser

How are American men and British men different? “U.K. guys – well, the ones that I know – don’t take as much stock in their appearance,” says Keira Knightley in a new interview. “Ask an American guy what his beauty regime is, and he’ll tell you. Ask a Brit, and he’ll say, ‘Er Guinness?’ I like that.”

In the July issue of InStyle, the actress, 21, does admit to an affinity for one American: Johnny Depp, her costar in 2003’s Pirates of the Caribbean: The Curse of the Black Pearl and its sequel, Dead Man’s Chest, out July 7. Asked which of her leading men was the best kisser, she says, “Johnny Depp certainly wasn’t bad.”

But there’s just one person she’s interested in kissing these days – her boyfriend, British actor Rupert Friend, 24, her costar in 2005’s Pride & Prejudice. But she insists that she and Friend, who played Mr. Wickham, didn’t get together while working on the film. “I haven’t ever had an on-set romance with anyone and I still haven’t,” she says.

Also in the InStyle interview, Knightley admits she’s uncomfortable dressing up: “I don’t know why I’m a scrub, but I am. I’ve got some great clothes and I’ll put them on, do my makeup and my hair, stand in front of the mirror and feel like such an idiot. I feel stupid if I’ve made an effort. It’s ridiculous.”

Nevertheless, Knightley – who was chosen by as one of the best dressed stars at this year’s Oscars – managed to have fun at the award ceremony when she was rendered “speechless” sitting next to Jack Nicholson. “I can’t remember what he said to me. Everyone asked if he tried to hit on me, but he didn’t. It’s actually kind of embarrassing that he didn’t.”

The new issue of InStyle hits newsstands June 23.