From Maisie Williams

Charles Dance has previously told us Maisie Williams is one of the most talented young actresses he’s worked with. (Maisie) Your first scenes with him in Season two as the cupbearer in Harrenhal have been described as some of the most intense in the series so far, were you genuinely petrified of Charles Dance?
When I first met him, I was very young and when he came in he was like ‘Hi I’m Charlie’ and I was like no your not your Charles Dance and it was just mad, but the weird thing about that when he came out on set I kind of forgot about it, because in Game of Thrones there’s so many people, sets and stunts when you just have a scene between two people talking. And you know it’s so different to most of the things that Arya does because she always in a fight or climbing something so, yeah it was great, I had such an amazing time and I learned so much from him, and such a pleasure to work with and he was hilarious. He was really, really nice and it was so cool that he said that about me.
http://www.heyuguys.co.uk/game-of-thrones-season-three/