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

We all know that Jessica Biel is no stranger to working out hard. We've seen the athletic actress running sprints at the track and doing crazy-hard boot camps. Well, Jess has signed on for a big adventure — climbing Mt. Kilimanjaro, the tallest, free-standing mountain in the world. The climb is part of an awareness and fund-raising campaign for Summit on the Summit, 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 read more.

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 back in August that he was planning to climb Mt. Kilimanjaro and it sounds like he has been training for quite some time.

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