Tonight we turn to a moment, a piece of video we discovered in a pact between a very young robin Williams and Christopher reeve, dear friends from acting school. ABC's Barbara Walters tonight with... See More
Tonight we turn to a moment, a piece of video we discovered in a pact between a very young robin Williams and Christopher reeve, dear friends from acting school. ABC's Barbara Walters tonight with that moment in the hospital room. Reporter: It was 1973. Two young men, part of 2,000 students who were auditioning for just 20 spots in prestigious juilliard school of drama. And they both made it in. Christopher reeve and robin Williams quickly became roommates and formed a friendship that would last decades, even after death. I just want to thank a very, very special person. Chris reeve, I miss you. And I also say may flights of angels sing three to thigh rest, sweet prince. Reporter: Legend has it the two of them made a pact as students -- that whoever "Made it" first would always support the other one. In 1995, reeve injured his spine in a horse riding accident and was paralyzed from the neck down. When I interviewed him four months later, he said the greatest gift Williams ever gave him was the gift of laughter. You had a very good friend named robin Williams. Yes, yes. And I understand that he came here to see you. I was hanging upside down semi-conscious. Not eating, not drinking. And I turned to my side and -- there is robin Williams dressed as a doctor wearing one of those funny blue scrub hats. For the first time since I crashed, I laughed. As I always do, as we always do with robin. Seeing him and laughing and enjoying each other like the old days was one of the first indicators to me that life could be good again. As you can see, David, robin Williams was the first person to make Christopher reeve want to laugh and want to live. A powerful promise they kept to one another and the reeve family speaking out. They said the world knew robin as a comedic titan, but to our family he was simply one of dad's dearest friends.
This transcript has been automatically generated and may not be 100% accurate.