Special Guest Stars Jon Lovitz voices Llewellyn Sinclair John Lithgow voices Himself Josh Groban voices Professor Frink (Singing) Guest Stars Maggie Roswell voices Luanne Van Houten Tress MacNeille voices Brandine Spuckler Kevin Michael Richardson voices Mark Chris Edgerly voices Actor playing Homer Tress MacNeille voices Chloe Pamela Hayden voices Lady Co Starring Okilly Dokilly as Themselves (End Titles Music Video)