She's in near constant danger in the world of Westeros on a weekly basis in Game of Thrones.

But Sophie Turner revealed that she's more concerned about co-star Kit Harington's off-screen humour than wildlings and white walkers, on Tuesday's This Morning.

Speaking about the mystery surrounding Kit's on-screen death at the end of the show's fifth series, the 20-year-old beauty admitted she'd been so convinced by his lies that she wrote him a 'heartfelt' goodbye letter.

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White Walkers or Kitt? Sophie Turner revealed that she's more concerned about co-star Kit Harington's off-screen humour than wildlings and white walkers, on Tuesday's This Morning

However with the actor - who plays fan-favourite Jon Snow - firmly back in the show for at least another series, she revealed he's been 'taking the mickey' after reading her emotional missive.

Speaking of the their playful relationship away from the cameras on the HBO fantasy epic, Sophie (who plays Jon's half-sister, Sansa Stark) explained he kept the letter and has been playfully poking fun at her.

She told Holly Willoughby and Phillip Schofield: 'Kit told me in the fifth series he was going, and I wrote a really long letter about how much I was going to miss him and how much I like working with him.

See Game of Thrones updates as Sophie Turner reveals Kit Harington pranks her

Gullible? Speaking about the mystery surrounding Kit's on-screen death at the end of the show's fifth series, the beauty, 20, admitted she'd been so convinced by his lies that she wrote him a 'heartfelt' goodbye letter

'And then he comes back next season and said, "I've still got your letter, it's so funny!" And he shows it to people, just to take the mickey!'

Laughing along with Sophie Holly felt a pang of sympathy and exclaimed: 'That's so mean!'

But joking aside, Sophie - who got her big break in the adaption of George R.R. Martin's literature series in 2011 - explained that she really had no idea how big the global phenomenon was going to be.

If only you knew! She told Holly Willoughby and Phillip Schofield: 'Kit told me in the fifth series he was going, and I wrote a really long letter about how much I was going to miss him and how much I like working with him

'He does it to take the micky!': Speaking about their playful relationship away from the cameras on the show, Sophie (who plays Kit's on-screen sister) explained he kept the letter and has been playfully poking fun at her

Explaining that when she auditioned for the role having 'no idea' what job she was even going up for.

However it seems Sophie's standout role as Sansa led her straight to her newest and possibly biggest role yet - Jean Grey in X-Men: Age of Apocalypse.

Speaking about how she was cast by Bryan Singer for his latest Marvel romp, as one of the most famous comic book siren's ever created, she paid tribute to the show's bosses.

'I so wouldn’t be sitting on this couch without Game of Thrones': However it seems Sophie's standout role as Sansa led her straight to her newest and possibly biggest role yet - Jean Grey in X-Men: Age of Apocalypse

Screen siren: It's clear that Sophie is well on her way to becoming a Hollywood A-Lister, as she looked every inch the smouldering screen siren when she hit the Age of Apocalypse's London premiere, on Monday

She gushed to Phillip and Holly: 'I so wouldn’t be sitting on this couch without Game of Thrones.

And it's clear that Sophie is well on her way to becoming a Hollywood A-Lister, as she looked every inch the smouldering screen siren when she took to the red carpet at the Age of Apocalypse's London premiere on Monday night.

Choosing to steal the show with her daring and sexy esemble, the actress opted for a black Balmain body and beaded skirt combo.

Off-duty beauty: But Sophie proved she's not one to go down the multi-outfit diva route, as she simply changed her skirt for a pair of skiny jeans when she headed out on the town following the premiere

Featuring a corset-inspired upper design, the long-sleeved one-piece also boasted strategically-placed see-though sections.

But Sophie proved she's not one to go down the multi-outfit diva route, as she simply changed her skirt for a pair of skiny jeans when she headed out on the town following the premiere.

Sophie play a young Jean Grey, the X-Men's most powerful telepathic mutant, in the latest big screen adaption of Marvel's famous comic series.

Originally portrayed in the first three adaptions by Famke Janssen, Sophie also revealed during her interview that the Dutch actress had given her her blessing to take on the role of Jean, saying she told her to 'go for it'.

X-Men: Age of Apocalypse is released in the UK on May 18, and will hit screens in the US on the 27.