Former Frasier stars Kelsey Grammer, DAVID HYDE-PIERCE and John Mahoney are to reunite as a family again on an upcoming episode of cartoon series The Simpsons. The trio head a gang of stars who will be making animated guest appearances on the 19th season of the cult show. These include opera star Placido Domingo, 2008 Oscars host Jon Stewart and Lionel Richie, who will feature in the premiere episode on 23 September (07).