Madonna engaged in a banana sword fight with a Game of Thrones star during a concert in Sydney March 19. She just happened to pick actress Gwendoline Christie. Christie is best known for her role of Brienne of Tarth on Game of Thrones and her role as Captain Phasma in Star Wars: The Force Awakens. Wanting to learn some of Brienne's awesome sword fighting skills, she pulls out two "rhinestone covered banana flasks,? which for the uninitiated is a flask shaped like a banana and covered with rhinestones.