Gemma Whelan "almost" lost her 'Game of Thrones' role because she shared the news online.
The 36-year-old actress had no idea about the secrecy that surrounded the show when she bagged the part of Yara Greyjoy and so she didn't realise there would be a problem for her to update her CV with the casting details until she was given a warning by producers.
She recalled to The Sunday Times: "The first lesson I learnt was when I first got the job. No-one told me to keep quiet about it.
"I just thought it was normal to pop it on my Spotlight entry, so I wrote on my CV, 'This summer Gemma will be playing Yara Greyjoy in 'Game of Thrones'. And the internet went nuts.
"One of the lovely, lovely producers on Thrones called me into his office and said, 'This is very serious. We almost can't employ you because of this'."
Luckily, producers still went ahead with her casting, which Gemma revealed had came about as a stroke of luck.
The actress' background was largely in comedy and she was "desperate" for a role in a drama but she didn't think she'd be considered - but the HBO show's casting director had previously met with her for an unsuccessful audition for comedy 'Threesome' in 2011 and thought she'd be the perfect choice to play the formidable Yara.
She recalled: ""I watched all of season one and thought, 'There's no way I'm going to get this'.
"I'd done a couple of comedies, I was doing a bit of stand-up -- but a big HBO series? Not on the cards.
"I'd been desperate to be seen for drama, because I really wanted to do both... but it's quite hard to be considered in both categories sometimes, until you can prove yourself."
Gemma will return to screens when the highly-anticipated season seven launches next weekend but she has clearly learned her lesson about secrecy and won't give away much about what fans can expect for her alter ego.
She said: "When we left off season six, it was clear that Daenerys [Emilia Clarke] and Yara were off on a mission. And we left me on a boat -- so it would follow that you would find me on a boat.
"But I'm not ruling out being on land. How about that? Let's not rule out any land!"
And asked if she'll survive into season eight, she added: "Oh, don't be naughty. You know I can't talk about that."