Christopher Reeve‘s son Will revealed to People magazine ahead of the release of the upcoming documentary “Super/Man: The Christopher Reeve Story” that Robin Williams was the first person who visited his father in the hospital after Reeve was paralyzed from the neck down. Williams also managed to make Reeve laugh for the first time since the accident by pretending to be a Russian proctologist.

“Robin was dad’s best friend, and you show up for your friends,” Will said, adding that Williams and Reeve called each other “brother.”

“Our dad and Robin had a singular bond,” Will added. “They had a friendship that someone should make a movie about, but what shone through in that was just their love and respect for each other, and that never wavered. … No one was better at showing up with love and with the right dose of humor than Robin Williams and his wife Marsha, who we call our fairy godmother. We are still so incredibly close with her.”

Williams and Reeve first met in the early 1970s when they were studying theater at the Juilliard school. The “Superman” icon wrote in his 1998 memoir, “Still Me,” about meeting Williams for the first time.

“He wore tie-dyed shirts with tracksuit bottoms and talked a mile a minute,” Reeve wrote. “He was like an untied balloon that had been inflated and immediately released. I watched in awe as he virtually caromed off the walls of the classrooms and hallways. To say that he was ‘on’ would be a major understatement.”

“Super/Man: The Christopher Reeve Story,” the acclaimed documentary that premiered at Sundance and will open in theaters later this month, follows the late actor’s rise to superstardom as Superman, as well as his fight to find a cure for spinal cord injuries after he became a quadriplegic following a horse riding accident. Reeve’s family participated in the making of the doc, which includes personal archive material.

“It is a gift. We’re so lucky,” Will’s brother Matthew Reeve told Variety at Sundance. “We not only have his films to look at but a collection of home movies to dig up and go through and interviews on YouTube of him to pull up. Seeing things I hadn’t seen before didn’t change my perception of him but enhanced it…like some rare Australian interview done in 1977 that was uploaded and I didn’t know existed. It was pretty cool to see that and uncover a lot more material than we knew about.”