Trending Now: Robin Williams ‘had to be funny to survive,’ says Stellan Skarsgård – Fans React

Stellan Skarsgård is reflecting on his time with Robin Williams on the set of Good Will Hunting.

The Oscar-nominated Sentimental Value actor shared his memories of working with Williams at a Q&A following a screening of the 1997 drama in Los Angeles on Friday night.

“As a person, when you were alone with him, he was calm and he was nice, and he was lovely, and he could talk about anything,” Skarsgård said of his late costar.

However, he added, Williams seemed to shift into a different gear when multiple people showed up. “But then when a couple more people came to him, he suddenly would get up — to save himself, in a way,” Skarsgård recalled. “And I think it’s a thing he had from school. He had to be funny to survive.”

Gus Van Sant, who directed Good Will Hunting and moderated the screening event, remembered how Williams asked to perform more takes for nearly every scene. “Robin was the one that was like, ‘One more, one more, one more,'” the filmmaker said. “So we did 10 [takes] sometimes as opposed to maybe three, because he wanted to do a fast one, a slow one, a happy one, a sad one, a funny one, a not-funny one.”

Skarsgård added that he appreciated the breadth and thoroughness of Williams’ work on the Oscar-winning movie. “It was fantastic because, as you said, he wanted to do new takes,” the Dune star. “And he also had a thing that was kind of a necessity for him because… he’d get an idea about a joke, for instance, and he had to produce it and get it out of the body. He couldn’t live with it inside. And I felt all the time that he had three parallel brains working, and very fast!”

The Breaking the Waves actor said Williams’ robust performance style challenged him and the rest of his costars. “The good thing was that he did different takes and they were really different,” he explained. “Some were very dark, and some were very funny. And all the other actors, we were hanging in there. We were playing different kinds of scenes with him.”

Skarsgård also marveled at Van Sant and the Good Will Hunting editors’ ability to incorporate Williams’ footage into the film and achieve the appropriate tonal balance. “The material you got [from Robin] is very interesting, because you could have cut that role into becoming a very farcical role, or you could have cut it into becoming really depressive,” he said to Van Sant at the screening. “And you found your way.”

In the film, Skarsgård portrays Gerald Lambeau, the MIT professor who shepherds the brilliant Will Hunting (Matt Damon) as he explores complex mathematics. Gerald enlists his former college roommate, Sean Maguire (Williams), to serve as Will’s therapist, and the two friends butt heads about how to best mentor the young genius.

Despite his character’s academic accomplishments, Skarsgård revealed that he had never dealt with advanced math, and that he “didn’t try to” comprehend the more complicated subjects with which Gerald grappled. “I did not understand it,” he said. “It was far above my math knowledge.”

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The movie employed real-life mathematician John Mighton to coach Skarsgård through the jargon, and Mighton ended up playing Gerald’s assistant, Tom. “We had a very good math professor that taught us and that helped us,” the actor said of Mighton.

“You wanted to have him around all the time, so he was usually busy,” Van Sant added.

“Yeah, he sort of prompted me,” Skarsgård said. “If you were explaining something, the only thing you have to know is that it’s expressed the right way… You don’t have to really understand it.”