“Game of Thrones” cast member Aidan Gillen has joined the “Maze Runner” franchise as the main villain in the upcoming sequel.

According to The Hollywood Reporter, the Littlefinger actor will play Janson, also known as Rat-Man, in “Maze Runner: Scorch Trials.”

The “Maze Runner” was released on Sept. 19 and grossed more than $104 million since its premiere date, according to Box Office Mojo. For those unfamiliar with the “Maze Runner”, check out the film’s official synopsis below:

“When Thomas (Dylan O'Brien) wakes up trapped in a massive maze with a group of other boys, he has no memory of the outside world other than strange dreams about a mysterious organization known as W.C.K.D. Only by piecing together fragments of his past with clues he discovers in the maze can Thomas hope to uncover his true purpose and a way to escape. Based on the best-selling novel by James Dashner.”

Dashner is reportedly working on a prequel to his “Maze Runner” saga. The novel will be his fifth franchise installment titled “The Fever Code”, which will be released in 2016.

“From the very beginning, I’ve always wanted to write a prequel about Thomas, Teresa, Newt, Minho, Alby and all the Gladers that leads up to the very moment Thomas enters the Box,” Dashner told MTV News.

“There are so many things hinted at that will be fun to reveal in depth. For years, fans have made it abundantly and enthusiastically clear that they want the same thing, so now seems like the perfect time to give readers the story of how the Maze began.”

“Maze Runner: Scorch Trials” is slated to hit theaters on September 18, 2015.