Kristen Stewart is opening up about the anxiety she felt ahead of portraying Princess Diana in “Spencer”. 

In a new interview with BBC News, the actress admitted that she couldn’t open her mouth for two weeks before she filming started. 

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 “I had TMJ to the point where I was like, completely locked up,” Stewart explained. 

“I was like, ‘Huh, I guess I’m really nervous – I was really tripping out until we started.”

The “Twilight” star also spoke about the extensive research she undertook ahead of shooting the biopic.

“I read everything, I wanted every photo… watched all the interviews that I could get my hands on,” she remembered. 

“I watched ‘The Crown’, I watched every iteration of interpretation. I just tried to absorb her in an emotional and general way, and then trust the process, and expect her to show up.”

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Continuing, “I think to do her justice is to allow her to be impulsive. Anything I watched her in, whether it was an interview, or even in a still photograph, it always feels unpredictable. Like you don’t know what’s going to happen. And it’s because she has this vulnerability and this raw emotion that she cannot conceal. There’s no way to do a perfect impression of that.

She added, “You have to feel it, and it has to be yours. So I think I just had to relax.”