After watching Saturday's edition of The X Factor, Sugar asked Simon Cowell to fire the 'Young' singer.
The Apprentice star tweeted: "Get back here and do X Factor yourself and chuck Tulisa out. She knows nothing and talks rubbish."
Contostavlos replied: "u look like an ugly hobbit. Stop tweeting me & go & find some happiness! It's embarrassing u miserable old man (sic)."
Back in August the popstar called the British business magnate "a tw*t" after he proclaimed he didn't know who she was.
The argument continued today (November 25) with the 65-year-old tweeting just three hours ago: "Next PR stunt for @officialtulisa "My cat died of exhaustion and heart attack". SUN headline 'Tulisa agonises over her worn out p**sy'".
Contostavlos has pushed back the release of her album The Female Boss to December 3.
Watch Tulisa Contostavlos talk to Digital Spy below: