Sophie Turner feared she'd ruin 'X-Men: Apocalypse'.
The 20-year-old actress admits she was worried she would cause the superhero film to get terrible reviews.
She said: "This is going to be the worst X-Men so far, because I'm in it. When you're outside something, you think, 'That is amazing, I would love to be in that.' But when you are in it, you think, 'Is this going to be any good?'"
And Sophie, who rose to fame as Sansa Stark on the HBO television series 'Game of Thrones', also revealed she worries about the television show coming to an end as she hasn't got anywhere "bigger and better" to move onto.
She told InStyle magazine: "I kind of had a bit of a panic attack the other night as I was thinking about it. It's like graduating from high school, but it doesn't feel like a graduation, because I don't have a university to go onto that's bigger and better."
Meanwhile, Sophie previously revealed how she researched ahead of her role as Jean Grey in 'X-Men Apocalypse'.
She shared: "I just watched the movies. I did my research online but for the Phoenix stuff I thought the movies were the best thing to draw from.
"In terms of building up the character, we didn't want her to feel on the edge of letting go, we wanted her to seem so repressed, you saw no hints of the real power that she has except for when maybe she's like, having a nightmare, but we didn't want any flashy things until the final moment."
And Sophie has hinted she could make an appearance in 'Wolverine 3'.
About working with Hugh, who plays the clawed superhero, she said: "It's amazing because he's such an icon in the 'X-Men' universe and I was such a fan doing it. Everyone wants a scene with Wolverine. Just seeing Hugh Jackman work is inspiring."