With filming already under way, the long-awaited adaptation of Stephen King's "The Dark Tower" has added on more player to its cast.

Variety reports "Vikings" veteran Katheryn Winnick has joined the Sony Pictures/MCM fantasy epic, which stars Idris Elba as Roland Deschain, aka the Gunslinger, and Matthew McConaughey playing the villainous sorcerer the Man in Black.

First "Dark Tower" Set Photos Spotlight Demonic Nuns and More

Directed by Nikolaj Arcel, the film is the first part in an ambitious adaptation that calls for a big-screen trilogy, with interlocking television miniseries.

Written by Anders Thomas Jensen, Akiva Goldsman and Jeff Pinkner, the movie isn't a direct adaptation of King's 1982 novel "The Gunslinger" -- the first book in the "Dark Tower" series -- but rather, in the author's words, start “in media res, in the middle of the story instead of at the beginning.”

Opening Feb. 17, 2017, "The Dark Tower" also stars Abbey Lee, Tom Taylor, Fran Kranz and Jackie Earle Haley.