The kind-hearted actor and green campaigner will front a launch on 28 March (12) on late-night U.S. TV show The Colbert Report to highlight the ramifications of natural gas in America's water supply.

In a post on Twitter.com, he writes, ""I'll be on the ColbertReport Wed March 28 launching Water Defense's campaign to protect our water from nat gas. Fossil fuels have been poisoning America's water for too long.""

Late last year (11), Ruffalo brought salvation to stricken residents of a township in Pennsylvania by delivering a supply of clean water after their reserves were contaminated with chemicals.