Biel, U.S. actor Emile Hirsch, Ethiopian-born musician Kenna, U.S. recording artist Lupe Fiasco and Gore, who is an executive with the United Nations Foundation, are part of a group making the 19,340-foot Summit on the Summit trek up Mount Kilimanjaro to raise awareness and funds for global water programs.
"It's pretty gnarly," Gore told People.com by satellite phone Monday, the fifth day of the climb. "The visibility is only 10 feet in front of you. And it's cold. I've got six layers on."
Asked how Biel, possibly the most famous member of the group, is holding up, Gore said, "Jess is doing awesome.
"She continues to bring levity yet seriousness at the same time," Gore told People.com. "We've played every game you can imagine -- travel Scrabble, word games. And there is a lot of free-style rapping going on."
Celebrity Couples of 2014 [PHOTOS]