It should come as no surprise that, in 1978, two distinctive aliens crash-landed into the cultural consciousness. There was Mork, the gonzo alien who stood on his head and spewed made-up words on the hit TV sitcom Mork & Mindy, which drew a whopping 60 million viewers a week at its peak, and Superman, the studly Kryptonian immigrant-superhero committed to saving Earth in Richard Donner’s film, Superman. These iconic characters were played by Robin Williams and Christopher Reeve, who just so happened to be the best of friends.

Williams and Reeve met back in 1973, as two of just 20 students accepted into Juilliard that year, and the only two to be accepted into the Advanced Program, taught by John Houseman. Reeve recalled first meeting Williams in his 1998 autobiography, Still Me.

“The first person I met at Juilliard was the other advanced student, a short, stocky, long-haired fellow from Marin County, California, who wore tie-dyed shirts with track suit bottoms and talked a mile a minute,” wrote Reeve. “I’d never seen so much energy contained in one person. He was like an un-tied 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. There was never a moment when he wasn’t doing voices, imitating teachers, and making our faces ache from laughing at his antics. His name, of course, was Robin Williams.”

According to Reeve, Williams blew away his fellow students, mastering virtually every accent in their dialects class and delivering comedic monologues that brought classrooms to their feet. But their primary acting teacher, Michael Kahn, had a hard time initially wrapping his head around Williams’s enormous talent. That is, until Williams’s turn in a production of Tennessee Williams’s The Night of the Iguana during their third-year acting class.

“Robin’s performance immediately silenced his critics,” wrote Reeve. “His portrayal of an old man confined to a wheelchair was thoroughly convincing. He simply was the old man. I was astonished by his work and very grateful that fate had thrown us together. We were becoming good friends. Many of our classmates related to Robin by doing bits with him, attempting to keep pace with his antics. I didn’t even try. Occasionally Robin would need to switch off and have a serious conversation with someone, and I was always ready to listen. For a time he had a crush on a girl in our class who thought he was an immature goofball. Robin was able to share his real feelings with me, and I always did the same with him. This has remained true for twenty-five years.”

Following the release of Superman II, Reeve became a bit disillusioned with Hollywood and moved his family to Williamstown, Massachusetts, where he played the lead in a theatrical production of The Front Page. One night, Williams paid his good ol’ pal a visit, taking in a performance and then taking him out to dinner after.

“Robin Williams came up to visit during the run and seemed to enjoy it tremendously,” wrote Reeve. “One evening we went out to a local seafood restaurant, and as we passed by the lobster tank I casually wondered what they were all thinking in there. Whereupon Robin launched into a fifteen-minute routine: one lobster had escaped and was seen on the highway with his claw out holding a sign that said, ‘Maine.’ Another lobster from Brooklyn was saying, ‘C’mon, just take da rubber bands off,’ gearing up for a fight. A gay lobster wanted to redecorate the tank. People at nearby tables soon gave up any pretense of trying not to listen, and I had to massage my cheeks because my face hurt so much from laughing.”

When he was honored by the Hollywood Foreign Press Association with the Cecil B. DeMille Award in 2005, the Golden Globes's lifetime achievement award, Williams dedicated it to Reeve:

The most touching anecdote in Reeve’s autobiography, however, concerns the actor’s recovery in ICU. After being thrown from a horse, suffering a cervical spinal injury that left him paralyzed from the neck down, Reeve was in a great deal of pain at the hospital. He even contemplated suicide. Since the accident had damaged his first and second cervical vertebrae, Reeve was forced to undergo a life-threatening surgery to reconnect his skull and his spine.

“As the day of the operation drew closer, it became more and more painful and frightening to contemplate,” wrote Reeve. “In spite of efforts to protect me from the truth, I already knew that I had only a fifty-fifty chance of surviving the surgery. I lay on my back, frozen, unable to avoid thinking the darkest thoughts. Then, at an especially bleak moment, the door flew open and in hurried a squat fellow with a blue scrub hat and a yellow surgical gown and glasses, speaking in a Russian accent. He announced that he was my proctologist, and that he had to examine me immediately. My first reaction was that either I was on way too many drugs or I was in fact brain damaged. But it was Robin Williams. He and his wife, Marsha, had materialized from who knows where. And for the first time since the accident, I laughed. My old friend had helped me know that somehow I was going to be okay.”

Williams was, of course, playing his kooky Doctor Kosevich from the film Nine Months, which had just hit theaters.

“And then we spent time together,” added Reeve. “He said he would do anything for me. I thought: My God, not only do I have Dana and my kids but I have friends like Robin and Gregory [Mosher] who truly care. Maybe it can be okay. I mean, life is going to be very different, and it’s going to be an enormous challenge, but I can still laugh, and there’s still some joy.”

The two remained the closest of friends throughout Reeve’s final years, with Williams joining his pal at several events in honor of The Christopher Reeve Foundation, which he wholly supported. Williams was recently asked what his favorite memory was of Reeve during a very revealing Reddit AMA.

“Him being such a great friend to me at Juillard, literally feeding me because I don't think I literally had money for food or my student loan hadn't come in yet, and he would share his food with me," Williams said. "And then later after the accident, just seeing him beaming and just, seeing what he meant to so many people.”

Reeve passed away after experiencing an adverse reaction to an antibiotic on Oct. 10, 2004. Williams, meanwhile, was found dead on the morning of Aug. 11, 2014, of an apparent suicide.

“My friendship with Robin Williams is one of the real joys of my life,” said Reeve. “Robin is a person who gives to people 24 hours a day. The gift of joy, the gift of laughter. Just to be in a room with Robin Williams is a privilege. He’s a gift to the world.”