Michael O'Connor
Keira Knightley, fashion chameleon

"WHAT does it feel like to wear a corset?" asks Keira Knightley, looking amused. The actress rolls her molasses-brown eyes and starts to gasp as though she's choking on a fish bone. "Your ribs are crushed in and you can't get your breath. Oh, and if you get emotional, you just can't calm down at all," she says as her chest heaves. She takes a deep breath and adds: "You can certainly understand why women were known as the weaker sex."Not that she's complaining, mind you. Knightley has come to understand how certain clothes make her a stronger actress. She appreciates the emotional strain of a mercilessly cinched waist and wig that towers 2 feet high. Or the physical discomfort of a 1930s...