Jessica Biel, Elizabeth Gore, Emile Hirsch, Lupe Fiasco and Isabel Lucas are on their way to Africa to climb Mount Kilimanjaro, the continent’s highest peak at more than 19,000 feet, and the world’s highest free standing mountain.

The “Summit on the Summit” expedition begins Thursday, aiming to raise awareness about the need for clean water worldwide.

Fans can follow the climb online with live updates and tweets, and donate as little as a dollar to sponsor a foot of the climb and provide clean water to those who need it.  One cent equals one liter of clean drinking water.