London, Jan 27 : Simon Cowell has given an ultimatum to both Sharon Osbourne and Dannii Minogue - that he'd axe them form The X Factor if they don't stop bickering.

The warning comes in the wake of the finalisation of contracts for the next series of the ITV1 mega-hit.

Sharon and Dannii's mutual loathing made 'The X Factor' conquer headlines for all the wrong reasons, during the last series of the reality show.

"It's nearly contract time again. Sharon said she doesn't want to come back with Dannii - and Dannii said she doesn't want to work with Sharon. But Simon has banged both their heads together and told them, 'If you don't shut up - I can replace you both'. They don't have to be best friends - but they do have to work together," The Sun quoted a source, as saying.

Last October, just before the first live show, 36-year-old Dannii was left in tears due to a last-minute row with TV favourite Sharon. The incident led to a subsequent media battle between the two.

The X Factor stars' contracts are due to be negotiated next month, and Cowell will want them signed soon after.

"Bosses know that viewers were hooked on the backstage battles between Sharon and Dannii and they want to keep them both on board - it makes for very interesting TV," added the insider.

The latest series of the telly talent show will hit screens later this year.

ANI