One is a beloved classic franchise of Hollywood-centric, musical theater-singing animal puppets. The other, a new hit medieval ফ্যান্টাসি প্রদর্শনী about killing people. So it's only a natural fit that they're mashed up together.
GoT has been readying the grand Girona Cathedral for a major scene filming this week, and people have spotted a great deal of crew activity, in front of and around the cathedral. It seems the crew has even gotten mischievous with onlookers.