Actor Edward Norton will appear alongside Alanis Morissette on Larry King Live tonight to promote Earth Hour. Norton is a long-time environmental activist while Morissette recently filmed a PSA promoting Earth Hour.

Earth Hour goes down on March 28th, when for one hour, 2,712 cities, towns and municipalities in 83 countries will switch off in observation of Earth Hour 2009, the world’s first global election between Earth and global warming. The concept is simple: turn your lights off to vote Earth and leave your lights on if you’re rooting for global warming.

Check out King’s interview with Norton and Morissette tonight at 9 p.m. on CNN.