Paul McCartney and Mariah Carey are the biggies being bandied about as possible special guests on the about-to-launch sixth season of American Idol. "Nothing's locked," executive producer Cecile Frot-Coutaz tells the Associated Press, referring to the former Beatle. "We've had discussions with him over the years. It's always a matter of making it work." The show's inside line on Mimi, meanwhile, is her good pal Randy Jackson. Recalling last season's surprise showing by The Purple One, Frot-Coutaz says, "The fact we can get Prince is a real tribute to the show. Who knows who we can get?" The only scary thought about Paul swinging by is, what, would it be for a "Wings' Greatest Hits" theme week? Or, "Say, Say, Say"?