This is a continuation of Question ID: 421463 
In that question, I said:
"Mikhail Gorbachev, since retiring from leading the USSR, has helped to
found the environmental group Green Cross International. Robert
Kennedy Jr., son of the former senator, is a lawyer for the Natural
Resource Defense Council, another environmental group. Jimmy Carter,
the former president, runs the Carter Center, which conducts
humanitarian missions to improve the lives of people in the third
world.

"Can you suggest a handful of other well-known individuals who are
active in social causes, especially environmentalism and/or helping
people in third world countries?"

The answer I got was good, but I would like some more names, with less
of a focus on actors and actresses.