Margaery is known for her signature cut-out dresses and cleavage. Her hair style also reflects that bare, sexy aesthetic, and it’s directly influenced by her gowns.
“What we did with Margaery that we hadn’t done with anyone else is we followed the line of the costume,” Alexander said. “We pulled so much more hair away, so it makes her more distinctive and different from everyone else,” Alexander said. (Sansa and Cersai usually wear their hair completely down.) “With Margaery, I wanted a lot more to be showing, I wanted a lot more flesh on her. We wanted there to be a little more sexiness.”
Mission accomplished, we’d say.