Ethan Hawke spoke on collaborating with Robin Williams on the film “Dead Poets Society” while accepting the President’s Award at the Karlovy Vary Film Festival.

The film earned four Oscar nominations, and it took home the prize for Best Original Screenplay. Williams, who passed away in 2014 at the age of 63, was nominated for Best Actor.

In the 1989 film, Williams portrayed an inspiring teacher at an all-boys school, in which Hawke had one of his earlier roles.

Off-camera, the two were considerably at odds, with Hawke admitting that he didn’t realize he was the problem until much later in life.

“I thought Robin hated me. He had a habit of making a ton of jokes on set. At 18, I found that incredibly irritating. He wouldn’t stop and I wouldn’t laugh at anything he did,” Ethan said during a Q&A session at the 55th Karlovy Vary International Film Festival.

But the two ended up as friends. Hawke did say that Williams was instrumental in helping him land his first agent.

“He called, saying, ‘Robin Williams says you are going to do really well.’ There was this scene in the film when he makes me spontaneously make up a poem in front of the class. He made this joke at the end of it, saying that he found me intimidating. I thought it was a joke. As I get older, I realize there is something intimidating about young people’s earnestness, their intensity. It is intimidating — to be the person they think you are. Robin was that for me,” he remarked.

The author, actor, and filmmaker Hawke also discussed his career, adding, “Once I started doing some directing, my respect for acting went up.”

Hawke will soon be seen with Oscar Isaac in the Marvel television series Moon Knight.

He disclosed earlier this month that the real-life cult leader David Koresh served as the unique inspiration for his on-screen persona.

Hawke also discussed his forthcoming work, including a potential new film with “Boyhood” and “Before Sunrise” director Richard Linklater that would focus on transcendentalists in the late 1800s.

“They were the first leaders of the abolition movement; they were vegetarians; they fought for women’s rights. [Richard Linklater] is obsessed with how their ideas are still very radical. This could be a super cool movie and Rick is writing it right now. He is mad at me [for coming to Karlovy Vary], he thinks I should be at his house,” he stated.

Regarding his earlier collaborations with Linklater, Hawke said you could look at the films as if they’re all connected. “I could make a case that ‘Boyhood’ is a prequel to ‘Before Sunrise’ — Ellar Coltrane is playing Richard Linklater’s surrogate and then I start playing Richard Linklater’s surrogate. It’s like the Marvel universe!”