The 'Game of Thrones' actress began dating the 27-year-old singer last year and though they are ''very happy'' together, she hates the constant scrutiny they are under.
She said: ''You do feel like you're living in a fishbowl. It's frustrating [that] it's the most mundane things that make the news - how boring!''
However, the 21-year-old beauty admits she prefers the fan name 'Mophie' for herself and 'Game of Thrones' co-star Maisie Williams over 'Jophie' for herself and the 'Cake by the Ocean' hitmaker.
She admitted to the new issue of Marie Claire magazine: ''I prefer 'Mophie'. What's that thing they say? Relationships come and go but friendship is always there.''
Sophie has no qualms about being ''rude'' to fans if she feels they have overstepped the mark in trying to take pictures of her when she's out in public.
She said: ''I find it really rude, and I will be rude back,'' she said. ''It's such an invasion of privacy. I could be out with my mum on her birthday and I will ask them to delete it. I would much rather them come up and ask for a photo. I will probably be fine with it...unless I look s**t!''
With 'Game of Thrones' set to come to an end next year, Sophie admits she will be distraught to say goodbye to her alter ego Sansa Stark, who she thinks has made her a more emotional person.
She said: ''It has been a huge chunk of my life. When it's done, it's going to feel like a death in the family.
''I just completely gave everything to her, all of my emotions. I never used to cry when I was younger. Now I cry all the time--I am an emotional human being.''
The actor says he isn't "holding out for more money or doing anything like that".
The drama will be making its return to the streaming service in the near future.
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