'Split' release date, cast news, plot spoilers: M. Night Shyamalan to bring 23 different personalities into one character

Famous for "The Sixth Sense," "Signs," and "The Visit," M. Night Shyamalan brings a psychological horror movie featuring 23 different personalities in one body. The actor who will play the role, James McAvoy, shared how he prepared for the challenging character of Kevin.

"Split" is a suspense-thriller featuring James McAvoy as Kevin, a character with a severe mental disorder called Dissociative Identity Disorder (DID). The film is directed by M. Night Shyamalan, and it is produced by "The Purge" and "Insidious" series producer, Jason Blum.

According to the official website of the film, Kevin has a total of 23 different yet visible personalities, which are all identified by his psychiatrist, Dr. Fletcher (Betty Buckley). Aside from the 23, which Dr. Fletcher is trying to merge into one, there is still an unknown personality that will take control over all the others.

Kevin will be kidnapping three teenage girls, with Casey, to be played by Anya Taylor-Joy, being the leader of the group. In the official trailer for "Split," Casey will try to sway some of the personalities to set her and her friends free.

In an interview with iHorror, McAvoy shared he had always wanted to work with Shyamalan, and he went on to describe how the director approached him for the role of Kevin.

"He told me to prepare myself for something different, something weird, and something that would be very demanding to play as an actor," McAvoy said.

The "X-Men Apocalypse" actor said that he researched cases of DID before production began in 2015. He added that he definitely believes that this type of mental sickness is real.

"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," McAvoy explained.

"Split" is scheduled to premiere on Friday, Jan. 20.