Heath Ledger barely had to say a word to score his breakthrough role as bad boy Patrick Verona in 10 Things I Hate About You.

The late actor was fondly remembered by the film’s director Gil Junger, who recalled being immediately struck by Ledger when he showed up to audition 20 years ago.

“Heath walked in, and I thought to myself, if this guy can read, I’m going to cast him. There was an energy to him, a sexuality that was palpable,” Junger told the New York Times as part of an oral history ahead of the film’s 20th anniversary Sunday.

Junger said that after Ledger, who was days away from turning 20 when the film premiered, read the first page of the script, he stopped him there and had him do some improv.

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“I just wanted to see how fast his mind would adapt, comedically. After 35 seconds, I said, ‘OK. Fantastic.’ But I could tell he was nervous that he blew it, because the audition was so quick, and I said, ‘No, no. You’re a very talented guy, and I really appreciate you coming in,” the director recalled.

Of course, Ledger hadn’t blown it – in fact, Junger had already made up his mind.

“The instant the door closed, I turned to the women in the room and said, ‘Ladies, I have never wanted to sleep with a man, but if I had to sleep with a man, that would be the man. Please cast him immediately,” he said.

10 Things I Hate About You, a modernized take on Shakespeare’s Taming of the Shrew, went on to become a teen classic, with its tale of a high schooler (Larissa Oleynik) attempting to set her sister (Julia Stiles) up with Ledger’s Verona in order to get around their strict father’s dating rules.

The film proved a breakthrough role for Ledger (thanks in part to his swoon-worthy performance of “Can’t Take My Eyes Off You”), who died at age 28 on Jan. 22, 2008 after consuming a fatal mix of prescription drugs.

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“I know for a fact he was in recovery prior to his death. He was trying to get healthy,” costar and friend David Krumholtz told the Times. “I just want people to know there was a suffering individual there, who couldn’t have been a lovelier human being. I prefer to remember Heath as a 20-year-old kid doing his first American lead with a big giant Cheshire grin smile on his face, taking charge as the leader of the group like any good ensemble leader should.”