Ethan Hawke wouldn't be Ethan Hawke without Robin Williams. The award-winning actor reflected on the late Williams this week, speaking about the influence that his Dead Poets Society costar had on his career.

"Look, this guy got me my first agent," Hawke, 43, said of Williams while speaking to CBC Q Radio's Jian Ghomeshi at the Toronto International Film Festival. "I'm here at the Toronto Film Festival, that agent is gonna be at the premiere of Good Kill tomorrow night. We know each other because Robin called his agent and said, 'You know, I think there's somebody good on set I met and you should meet him.' I owe that to him."

Hawke connected with Williams, who passed away last month at the age of 63, while he was earning one of his first major film credits for the Oscar-winning Dead Poets Society back in 1989. The agent that he met through Williams got Hawke booked for 1991's White Fang, launching a celebrated Hollywood career that has earned him three Oscar nominations so far. 

Back then, a teenaged Hawke was aware that his mentor Williams was privately struggling.

"Even at 18, it was obvious that he was in a tremendous amount of pain," Hawke said of the late Williams, who committed suicide on Aug. 11 after a lifelong battle with depression. "I don't know to what extent his whole life… Anybody who was watching knew. A lot of people aren't watching, actually, because he's so funny and so light."

Celebrated for both his comedic and dramatic genius, Williams kept his inner turmoil well-veiled from his fans. He had audiences in hysterics with his roles in Aladdin, Mrs. Doubtfire, and Mork & Mindy, and moved them to tears in Good Will Hunting and Dead Poets Society, among many other performances. 

"He moved us all," Hawke continued of Williams. "There was a very serious mind there. He was also so sentimental, just this big, sensitive heart. When we lose a great, great clown — that's what he was — there are people who are scared of that word a little bit, but he was a light for the world."

When Williams' light dimmed, it was a shock to many. 

"I feel like there's an immediate sadness that is pervasive in the whole community when somebody who made all of us so happy reveals themselves to have been in tremendous personal pain," Hawke added. "The happiness wasn't reciprocal. We didn't make him happy. That somehow rings to all of us."

Watch Hawke discuss Williams in the video above.