Matt Damon went to the Sahara Desert to scout locations for a movie about long-distance runners. But when he got there, he took on another project: helping bring clean water to Africa.

Damon and the production team behind the upcoming documentary "Running the Sahara" created a charity to accompany their filmmaking expedition in Africa, which gets under way this month.

During his preliminary visit to the continent, Damon, 36, said he "saw firsthand the effects of one of the largest public health issues of our time — the world water crisis which is at its worst in Africa."

H2OAfrica aims to raise awareness about Africa's water needs and support clean-water programs.

"Running the Sahara" is a documentary that will follow three ultra-marathoners as they attempt to become the first people to run across the Sahara Desert, which spans six countries. Along the way, the film's crew will identify locations in particular need of clean water so H2OAfrica can target its efforts. Damon will narrate the film. No release date has been scheduled.