Sadie Sink has revealed that she was genuinely terrified by Jamie Campbell Bower on Stranger Things 4 set. In an interview with The Holywood Reporter, she talked about her scenes with Vecna (Jamie Campbell Bower).
The actress said, "Well, I think two things come into play when it comes to the believability of Vecna. The first just being the prosthetics and having it be mostly practical effects was really helpful. We’re so used to working with stunt guys and stunt-women in green bodies and tennis balls in their hands, or something like that, so having Jamie actually there was very helpful because he was genuinely just horrifying. It’s just not normal what you’re looking at, so you’re kind of tricking your mind in a way, and it makes stepping into Max’s shoes that much easier."
She further added, "But also, I think the biggest part is that you can put anyone in that costume and they can be scary, but with Jamie, he was so in it all the time, not only when the cameras were rolling. He liked to kind of stay in character a lot, and there would be times and longer setups and stuff where he would filter in and out of it, but for a lot of the Mind Lair stuff, there was not a lot of talking going on between us. It was mostly just him as Vecna, standing in the corner and like growling or something like that, and he was just very, very, in it. And he would kind of talk in that voice a lot. So, to have someone as committed as Jamie in a role like that, just made it really believable. I think that was probably the key."
Earlier Jamie has revealed that actors who had close scenes with him were genuinely terrified. In fact, he was so scary that he left Millie Bobby Brown in tears.