The star of "Milk" and "Into the Wild" is joining Jessica Biel, Lupe Fiasco, Isabel Lucas and Elizabeth Gore for a weeklong trek up Mount Kilimanjaro. The Summit on the Summit expedition, which begins Thursday, aims to use star power to help raise awareness about the need for clean water worldwide.
The 24-year-old Hirsch says the climb combines "an epic adventure with an educational process on the global water crisis." Fans can follow the climb online and donate as little as a dollar to provide clean water to those who need it.
Hirsch says he's ready for the more than 19,000-foot challenge, saying, "Put this on the books: I'm making it to the top."