Jessica Biel is climbing Mount Kilimanjaro.

The 'Illusionist' actress is joining a group of celebrity climbers, including actress Isabel Lucas and singers Lupe Fiasco and Kenna, for the 'Summit on the Summit' expedition in January.

The trek hopes to raise awareness about the need for clean water worldwide.

Speaking about the trip, Jessica said: "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."

Jessica's boyfriend, 'SexyBack' star Justin Timberlake, previously stated he was planning to join in the climb, which will also raise money for the Children's Safe Drinking Water Program, United Nations High Commissioner for ReFugees and PlayPumps International.

He said: "I've been training four times a week to get my VO2 - oxygen consumption - levels up to expand my lungs. We'll climb for a week straight, carrying 30lbs on our backs. It's going to be intense, but it's going to be so rewarding. We're going to be ready for it."

The climb to the 19,000 ft summit of the African mountain was organised by Kenna, whose father suffered from waterborne diseases growing up in Ethiopia.

He said: "We wanted to make sure there was a way people knew this was an issue and a way for them to do something about it. This is a global issue. It's not an Africa problem. It's not a South America problem. It's a world, global problem. In America, 11 million people go without water."