By Bronte Coy
No show takes secrecy more seriously than Game of Thrones.
Every single tiny detail released by its creators is rapidly dissected by the series' vast fan community - so it's no surprise they keep everything locked up tight until they're good and ready to share it with the world.
That's the lesson Gemma Whelan nearly learned the hard way, after landing the role of Yara Greyjoy.
"When I first got the job... no one told me to keep quiet about it," she told the U.K. Times.
"I just thought it was normal to pop it in my Spotlight entry, so I wrote on my CV, 'This summer, Gemma will be playing Yara Greyjoy in Game of Thrones.'"