The Joker role didn't cause Heath's 'depression'

Heath Ledger is said to have been "exhausted, emotionally and physically” in the final weeks of his life, but his sister says his role as The Joker in The Dark Knight wasn't the cause of his tragic death in 2008.

Speaking at the premiere of I Am Heath Ledger at the Tribeca Film Festival, Kate Ledger refuted the claims that his method-acting for the Batman flick brought on a bout of insomnia leading to his fatal overdose of prescription drugs.

"Every report was coming out that he was depressed and that [the role] was taking this toll on him, and we're going, honestly, it was the absolute opposite. It couldn't be more wrong," she said.

"He had an amazing sense of humour, and I guess maybe only his family and friends knew that, but he was having fun. He wasn't depressed about the Joker."

Heath died in January 2008, with a toxicology report revealing a fatal mix of prescription drugs in his system.

Speculation that Heath's dark role had impacted his mental health began when Jack Nicholson, who played The Joker in the 1989 Batman film, said: "I warned him".

Earlier this month the documentary's director Derik Murray said the actor's final days painted a picture of a “very sensitive man” who was suffering deep "unhappiness".

“At some point in time, it unraveled for him,” Derik told People before adding, “I think it was tough for him to keep up with who he was.”

Meanwhile close friend and dialect coach Gerry Grennell, who lived with Heath while he was filming what would be his last film The Imaginarium of Doctor Parnassus said the star was battling illness and was “exhausted, emotionally and physically” in the final weeks of his life.

“I would hear him wandering around the apartment and I’d get up and say, ‘Come on, man, get back to bed, you have to work tomorrow.’ He said, ‘I can’t sleep, man,’” Gerry recalled to the publication, adding that Heath had been taking prescription sleeping pills to try and help him rest.

“He missed his girl, he missed his family, he missed his little girl - he desperately wanted to see her and hold her and play with her,” he added, referring to former girlfriend Michelle Williams and their then-two-year-old daughter, Matilda.

“He was desperately unhappy, desperately sad.”

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Heath died in January 2008, with a toxicology report revealing a fatal mix of prescription drugs in his system.

Earlier this month the first trailer for I Am Heath Ledger dropped, with the Brokeback Mountain star's sister Kate saying she believes her brother was piecing together footage for his daughter.

“You can tell her about things, but with her being able to visually see his movement and his expressions, it’s almost like he had actually filmed the documentary himself and pieced it together for her,” she told People.

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