“I read the books and I really, really wanted to play the part. I started kundalini yoga, kickboxing and running, and completely changed my diet. I felt I wanted to undergo what was necessary for the part. I love a challenge. And I love defying limitation, gender stereotypes and people’s expectations of me as an actress.”
Source : "Game of Thrones' Gwendoline Christie shreds Brienne of Tarth for super-seductive photo shoot" by Claire Rutter, www.mirror.co.uk. November 13, 2014.