"I was like, 'I cannot mess this up with a hangover,'" says the Game of Thrones star of tackling her biggest and most challenging role to date.

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Sophie Turner knows how important the Dark Phoenix storyline is to X-Men fans. As a kid in England, she read Jean Grey’s saga and connected to it. “Apparently, they were my favorite comics,” she says. “It’s just kind of funny I ended up playing her.”

But she also knows the pressure that surrounds both the saga and the role. “Are you kidding me? I’m so nervous. As you say, it’s one of the most iconic storylines so revered and popular. I guess the response to the third movie wasn’t great and there’s definitely a pressure to do it justice. I really believe in Simon [Kinberg] and I believe in all the work we did and I really really hope we did do it justice and I think we did but I hope the audience responds to it well.”

Credit: Doane Gregory/Fox

The actress, who plays Sansa Stark on HBO’s Game of Thrones, did not take the massive role lightly. She and director Simon Kinberg rehearsed for weeks prior to shooting and Turner studied multiple personality disorder and schizophrenia to capture Jean’s internal struggle.

It’s an emotionally and physically intense performance that also required a lot of green screen work as Phoenix’s fiery power grows (and Jean’s hair becomes a mass of flames). “I have a lot of respect now but people who work in heavy CGI movies where you feel like such an idiot doing it but you have to commit,” she says. “I think people think it’s like a vanity thing to play a superhero and to be in the cool costumes but you really have to put any ego aside to be wearing a bald cap, floating around.”

Credit: Twentieth Century Fox

Due to the intensity of the role, Turner admits she kept a very regimented schedule. “I think I had like two nights of proper partying and on a five-month shoot that’s not very much,” laughs the 21-year-old actress. “It was funny the first night that I went to bed early we were all at like this big group dinner and I had to work the next day and I was like, ‘Guys it’s 9 p.m. and I really have to be in bed.’ All the producers were so shocked because they know me and they were like, ‘Are you okay?’ You only really get one shot at something like this. I was like ‘I cannot mess this up with a hangover.'”

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