Robin Williams wasn’t just a famous Hollywood actor. He had a heart of gold and used it to help several causes. He aided 28 charities in his lifetime including St. Jude Children’s Research Hospital, disaster relief, and many more.

Everyone who met Williams loved him. He had a positive air about him that people couldn’t deny. It wasn’t just people though who fell in love with him. One particular gorilla, named Koko, fell in love with him the day she met him.

Koko is a special gorilla. She understands English and speaks fluently in American sign language. Williams was offered the opportunity to meet Koko and he jumped at the opportunity. What he didn’t realize is that Koko had been depressed and hadn’t smiled in a long time. She had just lost her long time friend Michael and was still grieving his loss. It was Williams who would turn her around and get her to smile again.

Williams visited Koko for the first time in 2001 at her home in the San Francisco Zoo. The two immediately hit it off with Koko holding Williams hand, asking him to chase and tickle her, and even wearing his glasses for a bit. The meeting was recorded for everyone to see.

Koko and Williams met again in 2004 when they joined together to film a commercial for the Gorilla Foundation. In 2014, when the death of Williams shocked the world, it also saddened Koko. When the gorilla’s trainers received phone calls of the news, Koko could sense from them that something was wrong. They knew they had to break the news to her.

They sat her down and her trainer explained to her what had happened. She bowed her head and her lip quivered with sadness. She seemed very somber and finally signed to the trainer that she was sad and crying. The two obviously had a bond that Koko will never forget. Watch the beautiful tribute video below to see Koko and Williams very first meeting.