According to an interview with WSJ. Magazine, Leto opted to wear specially designed contact lenses that made his eyes look opaque while simultaneously prohibiting visibility. It also required the Oscar winner to be guided around the set.
According to director Denis Villeneuve, Leto's reputation for intense method acting preceded him, but the level to which the actor took his character transformation still came as something of a shock.
"We all heard stories about Jared, how he transforms into the characters. But even this didn’t prepare me for what was to come," said Villeneuve, who characterized some of Leto's acting decisions as "insane."
However, the Sicario director had nothing but praise for the results, sharing, "He really created something. Every time Jared came on set, it was a boost of energy, tension and excitement."
Villeneuve revealed that the performer was going to impressive lengths to get into character before principle photography even began. During his first camera test, the director said Leto came into the room already in character.
"He could not see at all. He was walking with an assistant, very slowly. It was like seeing Jesus walking into a temple," he recalled. "Everybody became super silent, and there was a kind of sacred moment. Everyone was in awe. It was so beautiful and powerful -- I was moved to tears."