Harry Potter stars Rupert Grint and Emma Watson have vowed to keep any bad behaviour under wraps - so they don't get caught out by the press. The teenagers, who have become role models after appearing in the Potter films - as Ron Weasley and Hermione Granger, insist they won't succumb to the temptations of drink or drugs because they owe it to their fans to live good, healthy lives." Grint says, "You get the sense the media want a story of kid stars who go off the rails. We've all been pretty set on not doing that." And Watson insists the young cast has made a pact not to even smoke in public: "We're careful not to do all that... in the public eye."