But he has risked sparking a row with organisers by blasting the TV show, in which contestants battle for a record contract by singing their own versions of classic songs in a weekly knock-out competition, reports Contactmusic.
During a show at London's O2 Arena on Saturday, John said he would rather have his "c**k bitten off by an Alsatian (dog)" than watch the show. "My balls too," he added.
This is not the first time the singer has slammed the programme. In 2006, he told a journalist: "The X Factor is a cruise ship show. I've got nothing against the people who go on good luck to them. But I hate how they're treated."