Fans of Stephen King's The Dark Tower series of books could find themselves completely surprised by the movie adaptation of the author's work.

The first movie, The Dark Tower, will deviate from the books, at least according to new information being released by the film's production.

However, just how different will the movie be from its source material? New information suggests that hardcore fans might find themselves upset at some of the drastic changes. Fans were already dismayed at the casting of Idris Elba in the role of Roland Deschain, a character King once described as Clint Eastwood.

Yet, there are more changes in store for the movie. Here are the ones known so far.

Please note that the following contains spoilers from The Dark Tower books.

The Movie Doesn't Start At The Beginning ... Or Does It?

The Dark Tower movie will not begin with the first book in the series, The Gunslinger. Instead, previous reports state that the movie will actually begin in the middle of the story. However, those reports are sort of wrong.

At the end of King's books, Roland gains the Horn of Eld, and his entire story begins again. This is the gunslinger's cycle in his infinite search for the Man in Black. At the beginning of the movie, Roland will already have the Horn, suggesting that this is an alternate story, perhaps Roland's second or third adventure. So, it is sort of a beginning, and may follow part of The Gunslinger, but as an alternate journey for Roland, meaning that anything not in the books could happen.

"The hardcore fans of The Dark Tower series will know that this is actually a sequel to the books in a way," director and co-writer Nikolaj Arcel said to Entertainment Weekly. "It has a lot of the same elements, a lot of the same characters, but it is a different journey."

Eddie And Susannah Are Not In The Movie

Perhaps the most surprising news is that two of the books' main characters, Eddie and Susannah, will not appear in the first movie. That also explains why the film's production hasn't announced casting for the two roles. Don't fret, though: those character will turn up in later films.

"They're certainly out there," Arcel said. "I think the entire story deserves to be told and should be told. I would certainly be disappointed in myself or my collaborators if we didn't bring them in. They're such a huge part of the story."