One Direction

The global chart-toppers - who earned £100 million in the two years since they competed on 'The X Factor' - have reportedly declined an offer by boss Simon Cowell to mentor contestants on the show because they are too inexperienced.

Newly single Louis Tomlinson told The Sun newspaper: "We don't feel like we are in a position to be giving strong advice."

The group's mentor Simon is said to have been hoping the boy band would guest star in an episode of the UK reality TV series and conduct a master class with the current group of wannabe stars to help boost the show's ratings.

The 'One Thing' singers - who are nominated for two 'MTV Europe Music Awards' - recently appeared on both the Australian and US versions of the hit series, where they were a huge hit.

Harry Styles said the group really enjoyed being guest judges on the Australian 'X Factor', saying the experience was "really cool and fun".

But 'One Direction', who are set to release their second album 'Take Me Home' on November 12, are said to have ruled out a similar appearance during the current series of the British show on ITV1.