Coming Soon has the roster of guest voices to be featured in The Simpsons – Season 19, set to begin Sunday, September 23 at 8:00-8:30 PM ET/PT. Celebrities to be heard in upcoming episodes include John Stewart, Jack Black, Lionel Richie, Stephen Colbert, Matt Dillon, Kelsey Grammer, David Hyde Pierce and John Mahoney. In other Simpsons news, the soundtrack for the movie is available to hear legally free this week at AOL Music.