Koko, the gorilla known for mastering her own unique form of sign language and communicating with people, has died at 46 years old. The Gorilla Foundation announced that Koko passed away in her sleep on Tuesday morning.

As part of a Stanford University research project to see if humans and gorillas could communicate, Penny Patterson helped Koko learn over 1,000 signs and understand around 2,000 spoken English words. Her ability to communicate with others made headlines. In addition to making strides in gorilla communication research, Koko spent a lot of time in the media and hanging out with some well-known musicians and other celebrities.

Here are just some of the people Koko got to met. Other celebrities included Dian Fossey, Jane Goodall, Sting, Leonardo DiCaprio, and Peter Gabriel.

Robin Williams

When Robin Williams and Koko met in 2001, she singed Williams to tickle her. At one point she pulled Williams's wallet out of his pocket, taking out his ID as if she wanted to check and see if he was the real deal. When she was handed a DVD case of a movie he was in she even pointed to him on the cover when she recognized that it was him.

https://www.youtube.com/watch?time_continue=230&v=I9I_QvEXDv0

Betty White

When Koko and Betty White met in 2004, the two quickly became friends. White connected with Koko and saw the humanity she had. After meeting Koko, White served on the Gorilla Foundation's Board of directors for more than 10 years after.

Mister Rogers

Mister Rogers did a special episode of his show with Koko, about accepting differences. When he came to see Koko so they could film for the episode, she recognized him from watching his show on TV. She asked him about his cuff links and taught him how to sign the word "love."

William Shatner

While recording his audiobook, Up Till Now, William Shatner looked back on his visit with Koko as a publicity stunt, how he was originally scared to meet her, and how they had a surprisingly close encounter.

Flea

The Red Hot Chili Peppers had been a fan of Koko since he first saw pictures of her in the '80s, and learned about everything that she could do. When the two met, he played his bass guitar for her and thought her how to play herself. He even showed her how to tune the bass and said he had a great experience connecting with her.

https://www.youtube.com/watch?v=849IWyZgd7U

Simone Cazares is a student at Saint Paul College. Originally from Miami, Fla., she survives Minnesota’s cruel winters by immersing herself in the Twin Cities music scene.