This is the body of a woman who works hard. Thanks especially to movies like King Arthur (which, by the way, Guinevere kicks @$$), Knightley has adopted an extremely hardcore workout.
However, a body this good makes people suspicious. Knightley just recently ended a lawsuit against an English tabloid magazine that essentially blamed her for the death of an anorexic teenager. The tabloid posted super-skinny pics of Knightley (on the beach and such) and suggested that she had an eating disorder. The headline read: "If pictures like this one of Keira carried a health warning, my darling daughter might have lived."
Knightley was rightfully offended. She won the case and was awarded $6000 (3000 pounds). She doubled that money, adding her own $6000, and gave it to BEAT, a charity for people with eating and mental disorders.
Super-skinny isn't my look of choice (thank goodness, because it is not in my genetic code), but if you can pull it off, rock it. Every body is beautiful, in every shape and size.