It looks like Jessica Biel [1] is taking her recent roll of the earnest Salvation Army captain Sarah Brown [2] in the musical Guys and Dolls to heart. She just volunteered to climb a mountain for charity.

We all know that Jessica Biel [3] is no stranger to working out hard. We've seen the athletic actress running sprints [4] at the track and doing crazy-hard boot camps [5]. Well, Jess has signed on for a big adventure — climbing Mt. Kilimanjaro [6], the tallest, free-standing mountain in the world. The climb is part of an awareness and fund-raising campaign for Summit on the Summit [7], a group dedicated to educating the public about the need for clean drinking water worldwide.

To see if JT will be joining her on the climb, just .

Jessica explained why she was joining the celebrity team of mountaineers, including Lupe Fiasco and Isabel Lucas, like this, "This is a basic human necessity that needs to be addressed now. [I want] to help any way I can in order to raise awareness toward the life-threatening clean-water crisis happening not only in Africa but around the world." On the boyfriend front, Justin told Jimmy Kimmel [8] back in August that he was planning to climb Mt. Kilimanjaro and it sounds like he has been training for quite some time [9].

Sounds like a fun adventure and a great cause. Go, Jess go!