Heath Ledger (left) and Gil Junger.Photo:Courtesy of Gil Junger

Heath Ledger (left) and Gil Junger

Courtesy of Gil Junger

Speaking with PEOPLE amid the teen comedy’s milestone anniversary, Junger, 69, says that he “cast [Heath] basically before he even spoke.”

“This guy was an old soul if you’ve ever met one,” the filmmaker adds of Ledger, who would have celebrated his 45th birthday on April 4.

The actor wasfound dead on Jan. 22, 2008, in his apartment. A toxicology report revealed afatal mix of prescription drugsin his system.

“It crushed me when he died, because I knew who he was. I knew he was not a drug guy,” Junger says of Ledger. “People change, obviously, but when I knew him … he wasn’t a drug guy at all.”

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Heath Ledger in ‘10 Things I Hate About You’.

Heath Ledger in ‘10 Things I Hate About You’

Not long before the actor died, Junger called Ledger’s agent Steve Alexander and told him he “finished this script that I basically wrote with [Heath] in mind” — which would be called10 Things I Hate About Meand, at the time, “was going to be a film that explored and exploded the myths ofsuicide,” though the theme of the still-in-the-works movie has since changed.

According to Junger, Alexander told him that Ledger “would love to work with [him] again,” but had made the agent “promise that for the next two weeks until [Heath] completes filming, no phone calls, only unless it’s an emergency,” as he was finishing up production onThe Dark Knightat the time.

“Ten days later, he was dead. From drugs to help him relax, break anxiety and sleep,” the filmmaker says. “It’s so sad.”

Heath Ledger in ‘10 Things I Hate About You’

“[Heath] walked in the room in one of these big casting sessions … I swear on my parents' life, I thought, ‘If this f—er can speak English, I’m going to cast him,’ " Junger recalls. “He just hadan energy that was undeniable.”

So undeniable, in fact, he adds, “I liked Heath so much as a person that I would literally ride to and back from work with him just to spend more time with him.”

Recalling the then-teenage Ledger’s “bizarrely mature” nature, Junger says he told the young actor his “life [would] forever change” once10 Thingscame out, and advised him not to “get lost in the bulls—. The friends that you have now should remain your true friendsthrough your entire career.”

“Any boy at 17 hearing that from a quasi-known director would be like, ‘Oh my God, he thinks I’m going to be awesome. I can’t wait. Holy s—. I’d better buy a house,’ " Junger adds. “And you know what his response was? ‘Yeah. Well, how about we worry about today? Because all I really want to do is be the best I can today.’ "

10 Things I Hate About Youis streaming on Hulu and Disney+.

source: people.com