Kristen Stewart Says Diana, William and Harry Were Like "An Unstoppable Beast" Together

To play Princess Diana in upcoming movie Spencer, Kristen Stewart had to do intense research into the late royal's life. For the actress, one of the most powerful aspects of Diana was her close relationship with her sons Princes William and Harry, as she explained in a new interview with Entertainment Tonight.

Remarking on how skilfully Stewart embodies Princess Diana, the interviewer asked, "what part of getting her right were you most nervous about or did you work the hardest at in the physical transformation?"

Stewart knew exactly what to say to this. "Probably in the area that requires zero preparation and complete trust and like soul, which is the relationship that she has with her children," she answered. "You know, obviously, we [she and the actors who played the young princes] like hung out and tried to get [close] before we actually did the thing and did the scenes, but the whole thing about watching her within that space, when her children are close to her, they are ... it's a nucleus, it's a three-headed animal, sort of unstoppable beast thing."

For Stewart, there was something primal and instinctive in the relationship between this mother and her two sons, royal or not. "I feel, like, a reverence for that image that is not like ... you know, it's a pretty universal image," she continued. "You don't wanna mess with moms. You just don't do that, and I just... I think she feels so embodied in herself when she's with her kids in all of the research, that I was like, 'man, you know, that's what we're protecting here.'"

Stewart received a standing ovation for her performance in Spencer at the Venice Film Festival, and that's only one of the million reasons I. Just. Can't. Wait for Nov. 5, when the movie hits theaters.