Ledger, who reportedly plays a terrifying new version of the Joker in "Knight," died in January of an accidental prescription drug overdose. Ledger, 28, left behind a 2-year-old daughter, Matilda.
"Because he died people want a dark story (that) he was so obsessed with the character, he was so contaminated by the Joker and he couldn't sleep and all of that stuff," People.com quoted co-star Gary Oldman as saying. "In between takes he would sit on the curbside and smoke a cigarette, and laugh and talk about his daughter Matilda. I thought he was just wonderful."
"Heath showed me pictures of (Matilda) ... . (He) would come in and say she did this and she did that," added co-star Aaron Eckhart.
Director Christopher Nolan described working with Ledger as a "privilege."
"It's pretty amazing the disparity between the person he was and the monster that he created for us," Nolan said. "To see that being created from a this very gentle person is a real testament to his skill as an actor."