Jared Leto has some big shoes to fill when it comes to playing The Joker in the upcoming Suicide Squad movie. In 1989’s Batman the role was taken on by the legendary Jack Nicholson then in 2008 The Joker was reimagined through Heath Ledger’s portrayal in The Dark Knight, but now it’s Leto’s turn to make the role his own.

Jared Leto as The Joker in Suicide SquadJared Leto as The Joker in Suicide Squad.

“You’re kind of walking upon hallowed ground, and it deserves the very best that you can do,” the Oscar winner told Entertainment Weekly. “It takes over your life and that’s what I needed to do for myself.”

As part of his preparation for the role Leto met with psychiatrists and their most damaged patients to understand the mindset of a sociopath. However in the end the actor decided to rely on his instincts, just like The Joker would do.

More: Viola Davis: "Jared Leto Sent A Dead Pig To 'Suicide Squad' Cast"

“You don’t know what the Joker is going to do next; you never do,” Leto said. “It was intoxicating to have no rules.” During filming Leto was so engrossed in the character that even his co-stars weren’t safe.

On set he once sent a live rat to Margot Robbie (who plays Harley Quinn) which the actress ended up keeping as a pet and naming Rat Rat. She later told Elle magazine she kept it because: “If Harley got something from Joker, she’d probably cherish it.”

More: Why Will Smith Signed On To Play Deadshot In 'Suicide Squad'

But when filming wrapped he gave his co-stars some pretty strange parting gifts, including a boxful of nude magazines, a dildo, a switchblade, and a used condom. Co-star Karen Fukuhara said: “The wrap gift was his fun way of getting back at all of us. I wanted to keep everything.” 

Speaking about Leto’s commitment to the role director David Ayer said: “As an actor, he’s flinging himself into the abyss on that one. And he was scary on set. He was intimidating. He’d show up and it was like, ‘Dude, you are f***ing creepy.’”