Jared Leto is no stranger to fully immersing himself in his characters — he lost 40 lbs for his Oscar-winning role in “Dallas Buyers Club,” gained 60 lbs to play John Lennon’s killer in “Chapter 27” and gifted his Harley Quinn (Margot Robbie) a live rat while shooting “Suicide Squad,” in which he plays the Joker. And as more details emerge about his preparation for his Joker role, it gets more interesting.

Leto recently spoke about how he’s prepping for the role, giving audiences a glimpse on how he crafted and perfected his creepy take on the iconic Joker cackle, which has been featured prominently in trailers.

“I worked on the laugh walking around the streets of New York and Toronto, and I kinda would walk around the streets and see what laughs would get under people’s skin,” Leto told the hosts of CNBC’s “Squawk Box.”

“You know when you hear someone laugh at a restaurant? It’s a little jarring. I tried them out. And I kind of got to a place where I would laugh and people are always turning around like, ‘Who is this creepy guy behind me?'” he added.

When co-star Jai Courtney, who plays Captain Boomerang, spoke to MTV about Leto’s role he said, “I don’t know how you measure that these days. I haven’t seen him, since we started working, out-of-character, let’s put it that way.”

The Joker will be unveiled when “Suicide Squad” hits theaters on Aug. 5.