Matt Damon says he doesn't want to be one of those celebrities who lend their name to a charity, get great publicity and then forget about it.
The Oscar-winner explains that his involvement with the Toronto-based charity OneXOne is not about personal glory.
"Nobody involved with this movement is doing it for attention and accolades, starting with (U2's) Bono and (UN special adviser) Jeffrey Sachs," he said in an interview Sunday hours before a gala fundraiser he was hosting for the charity.
A trip last May to the African country of Zambia was "life-changing," Damon says, and inspired unbridled enthusiasm for the cause.
"I want people to know that these problems can be solved, that it's not impossible and it can be solved in our lifetime. If we don't do it, the outlook for the world is extremely bleak, and if we do, it's truly wonderful and this is about the world that we're leaving behind for our kids."
Damon said he thought seeing so much poverty and suffering would leave him depressed, but instead he returned from Africa cautiously optimistic.
"I feel like everyday Canadians and everyday Americans are good souls and they want to help," he said.
"It's just confusing sometimes how to help, and also sometimes people can feel overwhelmed and feel like it's hopeless and feel like it's a mountain we can't climb. I really want to do my best to dispel that notion because that was not my experience at all."
Joelle Adler, founder of OneXOne, sings Damon's praises, saying there are celebrities who promote charities to enhance their status, and then there are ones like Damon, who has quietly been doing philanthropic work without a desire for publicity.
"Matt is a genuine, committed person to Africa," she says.
"When you hear him speak, the passion he evokes, and when you see the way he's conducting himself now ... he's not here to discuss his movies, he's here to concentrate on the causes."
Damon says it was his trip to Africa that made him feel qualified to drum up support for OneXOne.
"I am an actor, but I do feel it's incumbent on me to go and learn as much as I can firsthand about what these issues are before I talk about them," he says.
"I think it's annoying to anybody when they see somebody mouthing off about something they don't know anything about."
Damon and the documentary team will follow the runners and capture their journey though six different African countries, along the way learning about the places and the people they meet.
Will Damon be running alongside the three men? After he finishes laughing, Damon says the men are completing the run in 80 days.
"If I ran across the Sahara it would take about four years."