Elizabeth Gore of the United Nations Foundation says Jessica Biel is "kicking butt" as she and other star-studded climbers trek up Mt. Kilimanjaro, Africa's tallest mountain at 19,340 ft. The group took off on the excursion to raise awareness of the global water crisis, and only two days in were hit with torrential rain. "The climb is really tough," says Gore, "but I'm proud to say no one has turned back." Weather aside, the group is handling the climb well and even finding time for fun. When they reached 13,600 feet, rapper Lupe Fiasco and musician Kenna joined locals in a singing contest. Other climbers include Emile Hirsch of Into the Wild, Alexandra Cousteau (Jacques Cousteau's granddaughter), and Kick Kennedy (Robert F. Kennedy's granddaughter). After Jan. 12, when the group plans to reach the summit, they will head to a UNHCR refugee camp in Ethiopia and visit the village where Kenna's family grew up, both areas plagued by a lack of clean water.