Koko who is very fluent in the American sign language met Williams in 2001 where they laughed a lot. The Gorilla Foundation reveals that after knowing about Robin William's death, she signed her word for 'cry' and also seemed very 'quiet' and 'thoughtful.' Meeting Robin made Koko happy as she had not smiled for over 6 months after her companion, Michael died.
Here is the video:
ALSO READ: 5 most loved comedic acts by Robin Williams