Matt Damon deliberately takes a light-hearted approach to his charity work in case the public is put off by preaching celebrities.
The Bourne Identity star is a high-profile campaigner for Water.org, which helps to raise awareness of the millions of families around the world who have no access to clean drinking water.
He fears potential supporters are put off by public figures ordering them to be more charitable, so he takes part in amusing stunts instead, such as calling for a "toilet strike" earlier this year (13), insisting he would not use a bathroom until the drinking water issue is resolved.
Damon tells British newspaper The Guardian, "People feeling preached to by privileged actors. I get that totally. I don't want some Hollywood actor finger-wagging at me, telling me what I should and shouldn't do... There's just no reason so many children should be dying, but if you say that, people go, 'Oh, shut the f**k up', you know what I mean? So you say, 'I'm going on a toilet strike'."