Why has Simon Cowell let Harry Hill write an X Factor musical?
26 March 2014 Last updated at 23:52 GMT
Simon Cowell has described X Factor spoof musical I Can't Sing! as "painful at times".
Speaking at the opening of the show at the London Palladium, writer Harry Hill said the show was an "affectionate spoof, and occasionally we go for the jugular".
I Can't Sing! stars former EastEnders actor Nigel Harman as X Factor supremo Cowell, in the show about a young woman who auditions and finds fame on the reality show.