MAMONI VALLEY PRESERVE, Panama (CNN) -- A famed primatologist says the plight of chimpanzees helped inspire Michael Jackson to write the song "Heal the World." 

Michael Jackson loved chimpanzees, said Jane Goodall: "They made him smile." 

But the theme and the lyrics of the song turned out to be about a better world for humanity. 

"He wrote what he told me he thought was his most powerful song ever, but it didn't end up for animals," Jane Goodall said in a CNN interview Thursday night. 

Goodall spoke exclusively to CNN in a Panamanian rain forest where she is exploring a partnership on behalf of Roots & Shoots, her global youth education program. 

The interview comes as a new version of the song, first released on Jackson's 1991 "Dangerous" album, is being recorded by a collection of artists for release in late October. 

Goodall became friends with Jackson about 20 years ago when he invited her to his Neverland Ranch, where "he talked about his dreams for the place to have animals running, looking free like they would in the wild. ... It was just a very charming day, very low key, nobody else was there," she said. 

Goodall, famous for her 50 years of groundbreaking research on chimpanzees in Africa, said Jackson invited her because "he loved what I did." 

"He loved chimpanzees," she said. "He loved to watch them feeding. He liked their faces. They made him smile." 

Years later, she met Jackson's chimp, Bubbles, and has visited him at his retirement refuge in Florida, she said. 
Where is that animal now?
Years later, she met Jackson's chimp, Bubbles, and has visited him at his retirement refuge in Florida, she said.