Matthew McConaughey's "devilish quality" landed him his role in 'Dark Tower'.
The Oscar-winning actor stars as the Man in Black, aka Walter Padick, in director Nikolaj Arcel's adaptation of Steven King's fantasy saga, and he had a great time playing a character who wasn't an "apologetic bad guy".
Arcel said: "One of the first things I told the producers was I really wanted McConaughey to play the Man in Black because I was a fan.
"I'd just seen him in 'True Detective' and 'Dallas Buyer's Club' and I thought he had that devilish quality to him, even though he usually plays good guys ...
"He hadn't read all the novels, he'd read the first one which he loved, and when he read the script he was like, 'Great, so I'm kind of playing the Devil here.' And I was like, 'Sure'.
"He was relishing the fact this wasn't the apologetic bad guy. I know it's a big trend, and I agree with that trend, that for villains in modern cinema you have to figure out what their motivation is and it can't be pure evil, but for Walter ... really he is pure evil. There's no redeeming him. Matthew was like, 'I'm going to enjoy this', and he certainly did."
And for the director, "coolest badass" Idris Elba was his immediate choice for the Gunslinger/Roland Deschain.
He told SciFiNow magazine: "There was a list of ideas for Roland and Idris was very high on that list. I was a huge fan from 'The Wire' and so on, so I immediately said, 'Well I think Idris Elba's the most exciting of all these to play Roland, and everybody was like, 'Yeah, we absolutely agree'.
"It's got to be Idris because he's the coolest badass. I just had to see him with the guns, he had this aura."