Jessica Biel, Emile Hirsch, Lupe Fiasco and Santigold star Santi White are among the group hoping to raise cash and awareness about the world's chronic water shortage by signing up for the charity climb to the 19,340-foot (5,895-metre) peak.
The Summit on the Summit posse set off on Thursday (07Jan10) and have been using the latest social networking technology to update fans and followers along the way.
In a recent 'tweet', climber Alexandra Costeau - the granddaughter of adventurer Jacques Costeau - writes, "2morrow we summit at dawn!"
And singer Kenna - the celebrity behind the big climb idea - adds, "Morning of. Actually slept. Can't believe it. This is it. This is the last day. We feel the Love."
The two movie stars have been joined by actress Isabel Lucas and pop stars Santi White, Lupe Fiasco and Kenna on the trek to the top of the 19,340-foot peak.
The star-studded group began the climb on Thursday (07Jan10) and are using the latest social networking technology to update fans and followers along the way.
They'll be posting posting clips, photos and 'tweets' on the Summit on the Summit website.