Eco-friendly actor LEONARD DiCAPRIO has added his name to a new campaign to banish junk mail. The superstar has signed a petition demanding the U.S. Government acts to allow citizens to opt out of unwanted post. Dubbed Do Not Mail, the campaign is the brainchild of international environmental group ForestEthics. DiCaprio's signature on the petition has been joined by fellow stars Adam Grenier, Darryl Hannah and Alicia Silverstone. Grenier tells PageSix of the cause, "Junk mail is more than an annoying waste of time, it's a waste of our environment!"