Simon Cowell has banned N-Dubz from going on The X Factor, despite the band's vocalist, Tulisa Contostavlos, being on the judging panel.

Dappy has said that he is devastated by the decision:

"We wanted to go on The X Factor to be with Tulisa on Judges' Houses but the people who own it thought we were too much of a gamble, that we wasn't right. Instead Tulisa's been given Jessie J. That's cool too. Jessie is amazing, she's great, and we love that. But still the whole thing is wrong. I'm devastated they don't think we're capable of going on there and helping her."

The rapper, who has been working on a solo career, has said that the move by Cowell is a joke and that he should "watch his back":

"Gary Barlow chose Robbie Williams and he got Robbie Williams. Tulisa wanted me and Fazer but didn't get me and Fazer. It's a joke...Simon, I'm coming for you, bro. I don't care, I don't give two s**ts - you've made a big mistake, man. Watch your back, Simon!"

Check out Dappy on BBC's Never Mind The Buzzcocks and an interview with them earlier this year for the TV show OK!: