Foster The People star Mark Foster and singer Kenna have reached the summit of Mount Kilimanjaro in Tanzania as part of a campaign to raise awareness about the global water crisis.

A video featuring the two friends on top of the world was posted online on Friday (11Jan13).

In the clip, obtained by RollingStone.com, Kenna, who organized a similar trip titled Summit on the Summit with Jessica Biel, Lupe Fiasco and other celebrities in 2010, says, "We're doing this project for clean water. We're here to make a statement because the global clean water crisis is such a huge issue."

Meanwhile, a bundled-up Foster admits he's struggling with the freezing conditions and high altitude: "I'm definitely feeling slow... and my brain is not working very well... I'm always in the back of the pack, just like, 'Guys, wait for me'."

Kenna now hopes to persuade his hero, Bono, to get involved in the campaign, explaining, "Bono has always been my main source of inspiration. I can't say I agree with everything Bono has done in history, but I do believe his focus has always been of great intent."

The two musicians were joined by actors Beau Jarrett and Justin Chatwin on the African mountain hike, which began on 3 January (13).