Umm skinny's not the word. Possibly and probably a size zero? Not natural/down to fast metabolism either as she used to be 'bigger'. That waist is thinner than my thigh by a long shot. Even DH said about it this morning and he's generally not interested in that sort of thing.
Don't understand why it hasn't even been mentioned in the press? I'm confident that any other celeb/person in the public eye would be questioned/accused of being anorexic.
I wonder what her BMI is? I would suggest dangerously low, NOT a good example IMO. However, gorgeous teal dress :)