Ethan Hawke is reflecting on one of the most defining experiences of his early career — working alongside Robin Williams in the 1989 classic Dead Poets Society.

During a recent interview with Vanity Fair for a career retrospective, Hawke discussed the profound lessons he learned from observing the late actor and director Peter Weir collaborate on set.

“I’m watching him direct Robin Williams, not an easy thing to do, ’cause Robin was a comic genius. But dramatic acting was still new to Robin at that time,” Hawke recalled.

“And watching that relationship like, in the room — I was four feet away while they’re talking about performance — and that was something you don’t unsee.”

Hawke said the experience transformed his understanding of creativity. “Robin Williams didn’t do the script, and I didn’t know you could do that. If he had an idea, he just did it. He didn’t ask permission,” he said.

“And that was a new door that was opened to my brain, that you could play like that. And Peter liked it, as long as we still achieved the same goals that the script had.”

The Training Day actor admired how Williams and Weir balanced their contrasting approaches. “They didn’t judge one another or resist one another,” Hawke said.

“They worked with each other. That’s exciting — that’s when you get at the stuff of what great collaboration can do.”

Dead Poets Society, which follows teacher John Keating (Williams) as he inspires students through poetry, went on to win the Academy Award for Best Screenplay and earn nominations for Best Actor, Best Director, and Best Picture.