Remember a few years ago when Gisele Bundchen and Tom Brady asked people to turn off the lights during Earth Hour? Well, Matt Damon is doing something of the sort, but with a sense of humor. In a tongue-in-cheek video launching on YouTube on Tuesday, Damon announces that he won’t use a restroom until everyone on Earth has clean water and sanitation. The video, the first in a series that will feature familiar faces from film and TV is intended to raise awareness about the global water crisis, a cause near and dear to Damon, who’s one of the co-founders of Water.org. We’re told it was Damon’s idea to use humor in the videos, hoping it works better than earnestness in attracting attention. Consider this: Damon’s funny video with Sarah Silverman has been viewed over 3.4 million times on YouTube, while some of his thoughtful vids on behalf of Water.org have been clicked only a few thousand times.