Britney Spears and Demi Lovato steal the show as Simon Cowell launches the US X Factor at special screening

Simon Cowell at the X Factor USA launch in Hollywood Credit: Reuters

Simon Cowell has been joined by Britney Spears, Demi Lovato and L.A. Reid at a special screeinng of the US X Factor.

Demi Loavto, Britney Spears and Simon Cowell at the screening Credit: @ddlovato

Spears and former Disney Channel singer Loavto made their debut as new judges on Wednesday when the show returns with early audition rounds filmed in the summer.

Spears, who wore a cobalt blue dress as she attended the event at Grauman's Chinese Theatre in Hollywood, said 'she was excited' at being at the X factor party.

Loavto makes her first public X Factor appearance Credit: Reuters

Fellow judge Lovato, who wore a retro-inspired fit-and-flare dress, said it was 'surreal' being at the X Factor screening.

Cowell, who fired Steve Jones, Paula Abdul and Nicole Scherzinger, after a disappointing first season on U.S. television, will hope the reveamp will win over viewers.

TV reality star Khloe Kardashian is being tipped to become the main presenter.

Simon Cowell at the X Factor USA launch in Hollywood Credit: Reuters

Daybreak's Ross King caught up with X Factor boss Simon Cowell.