When M. Night Shyamalan told James McAvoy to read the script for the writer-director’s latest film, Split, with an open mind, he wasn’t joking. McAvoy plays nine different characters in the film, all of whom live in the same body. “I met with Night, whom I’ve always wanted to work with, and he didn’t tell me much about the script before I read it,” says McAvoy. “He told me to prepare myself for something different, something weird, and something that would be very demanding to play as an actor.”

McAvoy’s character in Split, Kevin, suffers from a severe case of DID [Dissociative Identity Disorder]. Throughout Kevin’s life, his body and mind have played host to more than twenty different personalities, twenty-four to be exact. Nine of these personalities are featured in the film. “I’m only Kevin for about ninety seconds in the film, so it’s hard to say who Kevin really is,” says McAvoy. “I don’t think of him as just Kevin-I think of this as a community of personalities that live inside his body. The nine characters featured in the film all have a job, an objective. After reading the script, I immediately decided that I wasn’t played Kevin but nine different personalities. Making this film was almost like making nine different films at once.”

Split absolutely depends on McAvoy’s performance and his ability to convince the audience that they’re experiencing these different personalities throughout the film.  “Kevin comes from a horrible childhood, which was full of abuse and trauma,” says McAvoy. “This is how the different personalities developed inside of him-this is how he was able to deal with everything around him. Kevin’s body is very brittle because of his horrible childhood existence, and he started exhibiting a split personality disorder when he was three or four. Dennis was the first personality that developed, and then Barry, Hedwig, and Patricia came along to save him at different points in his life. Some of the characters have a broad bandwidth and some have a narrow bandwidth. Kevin and his personalities have been beaten and diminished throughout his life. “

Split is a psychological horror film, which explains the appearance of personality number twenty-four, who is known as The Beast. “As the film opens, the personalities inside Kevin are being slowly marginalized and reduced and pushed aside,” says McAvoy. “This makes some of them hostile. They feel like they’re in prison. The Beast appears as this benevolent god to Kevin and the rest of the personalities. The Beast appears as a godlike figure and makes them believe in themselves by teaching them that they’re special, and that it’s the world around them that’s sick. The Beast teaches them that not only are they normal but they’re extra normal. The Beast thinks of himself as an extremely pure being, and he’s very malevolent and nasty. The Beast controls the various personalities inside Kevin, and he pushes Dennis, who becomes the Beast’s henchman, to punish everyone who’s impure. This leads to the kidnapping of the three teenage girls in the film.”

The film opens with Kevin kidnapping three teenage girls who are then held prisoner inside Kevin’s house. “The interior of Kevin’s house is a bestial environment,” says McAvoy. “There’s beauty and horror. The personalities have been living underground, and the look of the inside of Kevin’s house reveals this. The Beast teaches them that they don’t have to live like that anymore. Dennis and Patricia bond with the girls, who begin to hear about the Beast, whom they don’t want to see. Patricia has a feminine connection with the girls, which the lead girl, Casey, tries to exploit. Hedwig has a juvenile attraction to Casey.”

McAvoy did research into DID and split personalities before he started work on Split, which began filming in Pennsylvania in the fall of 2015. Betty Buckley plays Dr. Fletcher, a psychologist who tries to help Kevin combine his various personalities into a single being. “I did research into DID, which I definitely believe is for real,” says McAvoy. “I don’t believe that people with DID are, in most cases, exaggerating or faking their symptoms. What I learned is that some DID personalities keep diaries , with one alter ego writing to another one, just so they can keep track of different parts of their lives. The personalities have different views about Dr. Fletcher and how they should be treated. Sometimes one personality pretends to be someone else in Dr. Fletcher’s presence. Dr. Fletcher is never sure what’s going on, which is how the audience will feel. Fletcher fights for them and tries to prove that DID does exist.”

McAvoy describes Split as a fun, intense, scary thriller with elements of black humor. “The most disturbing, frightening aspect of the film for the audience might be the sight of me in a dress, wearing lipstick,” jokes McAvoy. “There’s great tension in the film, and then Night finds a way to alleviate that tension at different points. Some of the alter egos are fun, interesting people to be around, and some aren’t.”

McAvoy has high praise for Shyamalan. “I’ve worked with several writer-directors so far, and Night is definitely one of the best,” says McAvoy. “He controls his films, and he takes possession of the story and every element of the process. He draws the entire film before he starts shooting, and he brings his vision from the drawing board to the screen. Night has a plan, and he carries it out throughout the filming. He also lets you in on what he’s doing, which builds a sense of trust. I’m getting old now, and I’m more and more willing to just do what a director tells me. Technically, Night is also way up there. He understands every aspect of the camera. He’s all over everything.”