Henry Winkler Knew Robin Williams Was a 'Genius' the Moment They Met at His “Happy Days” Audition

The late actor famously took on the role of Mork, the alien from Ork, on the beloved sitcom

Henry Winkler knew Robin Williams would become a star the moment he began his audition for Happy Days.

During an Oct. 1 episode of the Fake Doctors, Real Friends with Zach and Donald podcast, the actor, 78, recalled sitting in auditions for Mork, a Martian who visits Earth, after the original actor who played the alien left the show.

"When Robin came to audition, now it's Wednesday. We start Monday morning at 10 o'clock on the soundstage. That is at, 9 o'clock, we read. 10 o'clock, we're on the soundstage," Winkler began. "Nobody wanted to play this alien from outer space."

Related: Pauly Shore Recalls Robin Williams' Early Stand-Up Days at The Comedy Store: He Was 'Just Another Level' (Exclusive)

"Finally, a young, very shy, very quiet man comes with the casting director," he continued, noting how with a flip off a switch, Williams' timid personality changed. "And then this human being picked up the script. When he opened his mouth, it was like a volcano went off on stage 19 at Paramount."

"And I knew, get out of his way, know my lines, and don't try to stand toe to toe with this genius that is now standing in front of me," he added.

Williams made his debut as Mork, the alien from Ork, in season 5, episode 22. Titled "My Favorite Orkan," the episode centered around Richie (Ron Howard) and how no one believes him after he claims he saw a flying saucer and was interviewed by an alien named Mork, who tries to take him back his home planet as an example of an average human.

Winkler isn't the only one who was dazzled by the late actor's performance.

Related: Danny DeVito Remembers Crowds Watching Robin Williams Act On 'Mork & Mindy' Set

In 1989, Happy Days creator, Garry Marshall wrote a first-person narrative for PEOPLE where he reflected on the success of the hit show and discovering Williams.

"When Robin Williams came on as a Martian, he was all over the place and was improvising some, and they gave him room," Marshall said. "At the end of the episode, 300 people in the audience stood up and applauded, which is not usually done. It didn’t take a genius to know he could do his own show, and we made one for him, Mork & Mindy.

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories.

When he needed an actor to play the Martian, Marshall's sister Ronny was in charge of casting and insisted he allow Williams to audition despite his reservations. After suggesting she bring him actors Jonathan Winters and John Bryners to the audition room, she pushed for Marshall to "make time" for Williams after observing him in an acting class.

"So I made time, and he did the whole audition standing on his head. He was a whole different fresh view of a guy doing an outer-space alien," he added.

For more People news, make sure to sign up for our newsletter!

Read the original article on People.