Sony Pictures Entertainment's The Dark Tower has begun filming, Stephen King announced Wednesday.

Based on King's seven-book series, The Dark Tower film has been a long time coming. Idris Elba and Matthew McConaughey take on the main roles of the gunslinger (Roland Deschain) and the man in black (Walter Padick), respectively.

Mad Max: Fury Road's Abbey Lee will star as Tirana.

"The thing is, it's been a long trip from the books to the film," King said about The Dark Tower when it entered production. "I'm delighted, and I'm a little bit surprised."

King has described The Dark Tower as his magnum opus, wherein he created a world that ties together many of his novels. The Dark Tower is said to take place during the events of just the first book in the series.

Directed by Nikolaj Arcel (A Royal Affair), The Dark Tower is slated for a January 13, 2017 release.