X Factor's Greatest Musical Guests Ever: From Lady Gaga To Adele And Britney Spears

The 'X Factor' stage has played host to many big names over the years.

The start of the ‘X Factor’ live shows means many things. It means Christmas is not that far away *gulp*. It means the sight of Simon Cowell’s chest will become a regular Saturday night fixture. And it means that producers bringing out the big guns, signing up some of the biggest names in the music industry to put on a show for us, all in the name of flogging their new material.

Over the years, stars as huge as Celine Dion, Paul McCartney, Elton John, Cherand the late Whitney Houston have all hit the stage to perform for ‘X Factor’ viewers (not to mention Simon Cowell…), and we’re sure this year will be no exception.

But which act has had the most memorable ‘X Factor’ guest performance ever?

Show-stopping dance routines, wardrobe malfunctions and dodgy vocals - over the years, the ‘X Factor’ stage has seen them all, and these are just some of the guest performances that have stuck in our heads from series gone by (although it’s not always for the reason the artist was hoping)...

Best 'X Factor' Musical Guests