The actress has previously spoken of how her drama tutors warned her she would struggle to find regular acting work because of her 6ft 3in height.
Brienne, who she played for eight years, was her breakthrough role.
She has gone on to appear in Star Wars and recently played Titania in A Midsummer Night’s Dream at the Bridge Theatre.
Christie, 40, told GQ Style she had started to deal with the possibility of not getting another role like Brienne even before Thrones ended earlier this year.
She said: “It might never happen. But it’s OK. What occurred was a shift; something spoke to me and allowed me an insight into humanity.
“Thrones, and Brienne, together they gave me a lot of hope, and a lot of experience.
“I’ve been dealing with this idea of loss since I ﬁrst got the character. Now, it’s about stepping into other worlds and other humans and allowing that to happen. It was so hard for so long. But a little bit of acceptance means a huge amount.”
Christie has appeared on the catwalk as a model and embraced fashion while growing up because her height “seems to draw such extreme responses from people.”
She said: “It’s ﬁght or ﬂight, isn’t it? Sink or swim. You either exist in a state of shame about not ﬁtting into society or you embrace what you have.”
She added: “So many women come up to me and talk about what it means to feel represented outside of the constraints of conventional society.
“In 2011, I didn’t think I would ever see women that looked like me in mainstream entertainment. It felt like there was one mould that wouldn’t be broken. So the fact that Brienne existed? Wow.”
Read Christie’s full interview in the autumn/winter 2019 issue of GQ Style, available on Thursday.