The news of director Garry Marshall's death on Tuesday hit all of Hollywood hard, but perhaps one of the people most affected by his passing was his longtime friend and collaborator, actor Hector Elizondo.

"This should be a celebration. I'm trying to put myself in a [positive] frame of mind because it's been such a body blow, [and a] collective body blow too to so many thousands of people," Elizondo exclusively told ET. "He was my best friend, simply put."

WATCH: Garry Marshall Dies at 81: Stars Share Touching Tributes to Celebrated Director

According to Elizondo, the two met by chance on a basketball court in 1979. At the time, Elizondo was an up-and-coming stage actor and Marshall had already created The Odd Couple, Happy Days, and Mork & Mindy, just a few of the successful shows he would have a hand in during his storied career.

"No one had introduced us. Who knew television producers, right? You know, I was a New York stage actor, I turned up my nose at TV," Elizondo recalled. "[But] that's how we became friends."

"He did his first movie [in New York]: Young Doctors in Love. He pitched it to me after I accidentally hit him in the face with a basketball," he continued. "He said, 'Hey, that's not a good pass but I think we gotta talk about a movie.' … We got along instantly. It's like we had been friends for thirty years."

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After working together on the 1982 comedy, Elizondo went on to appear in every film Marshall directed, whether it was in a major role or a simple cameo. As it turns out, Elizondo couldn't have refused the parts even if he wanted to.

"I couldn't say no of course, because I found out years later I was in his contract," Elizondo joked, explaining that Marshall apparently had a stipulation for every film he signed on to direct, allowing him to cast his friend. "He never told me."

Marshall's kindness, generosity and interest in fostering talent were among the many virtues that Elizondo praised about the celebrated filmmaker.

"He was a kind man, an elegant man, and a loyal, loyal man," he shared. "He just elevated the atmosphere he was in. He mentored so many people. He loved seeing character in people. He used to say, 'Everybody has talent, Hector! Everybody has talent but it's the character that makes the difference!'"

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The 79-year-old actor also reflected on the legacy Marshall left behind, and explained how he thinks the iconic director, producer and performer would want to be remembered: "As a man who helped people. That's all. As a man who left the room a little better than he found it."

"I'm gonna miss him a lot," Elizondo said. "That's all I can say."

Marshall died on Tuesday due to complications from pneumonia, at the age of 81. Many of his friends and colleagues have taken to social media to share their love and appreciation for his illustrious career and his kind heart. Check out the video below to see some of the most touching tributes.