Jessica Biel joins celeb climb on Mt. Kilimanjaro

The entertainers have signed on to climb the continent's highest peak — Mt. Kilimanjaro, at more than 19,000 feet — to raise awareness about the need for clean water worldwide.

The Summit on the Summit expedition, set for January, is the brainchild of singer and producer Kenna. His father suffered from waterborne diseases as a child in Ethiopia.

Justin Timberlake — who's been romantically linked with Biel — may also be joining the climbers: He told GQ magazine earlier this year that he was preparing for a major mountain climb.

Representatives for the climb declined to comment on his possible participation.