Lord Alan Sugar claims Tulisa Contostavlos has no right to be an X Factor judge.
The outspoken businessman - who stars in 'The Apprentice', in which he tries to find a new business partner - hit out at the 'Young' singer on twitter, claiming she hasn't done anything to warrant her place on the judging panel of the ITV1 show and claimed she just talked "nonsense".
He wrote: "Can you tell me who the hell this Tulisa bird is on X factor,she's in the celeb section of the sun and mirror every day. What has she done?"
"This Tulisa talks nonsense on X factor,what qualifications does she have to judge singing talent.Please advise where I am missing the point. (sic)"
However, Tulisa - whose act Little Mix won last year's series of 'The X Factor' - hit back and said she was fed up with him always slating her.
She wrote on twitter: "Stick to judging on the Apprentice & I'll stick to what I know MUSIC #itsaNOfromme. (sic)"
She then followed it up with: "Soz bout that tweet peeps. But that t***t has been bad mouthing me since last year! (sic)"