Natalie Dormer from the Tudors has been casted to play Margaery Tyrell of House Tyrell.
Margaery Tyrell is the sister of Loras Tyrell. Margaery is an intelligent and shrewd young woman who is supposed to be very beautiful, with softly curling brown hair, brown eyes and a slender yet shapely figure.
I can't remember who I imagined Margaery to be while reading the books a few years ago but I can visualize Natalie playing this character well. She was a great Ann Boleyn in the Tudors.