Josh Hartnett was more starstruck meeting British Prime Minister Tony Blair than he has ever been on a movie set. The eco-friendly actor was in London yesterday (30JAN07) to launch an environmental campaign asking a billion people to reduce the carbon emissions they release into the atmosphere. And he confesses to being nervous in the presence of Blair: "It's very strange and makes a change from acting. It's quite exciting. It's a great cause and hopefully I can make a difference."