David Boreanaz

SISTER act Dannii and Kylie Minogue have told X Factor bitch Sharon Osbourne: “We are out to get you.”

The furious Aussie duo plan to confront her at tonight’s big finale. And they aim to get her booted off the show for good.

Dannii, 36, and Kylie, 39, are furious over Sharon’s comments on a chat show this week in which she cruelly compared pretty Dannii’s face to her saggy old BUM.

It was the latest in a string of vicious attacks by bitter Sharon, 55, on her sexier and younger rival judge.

But now Dannii has had enough. And tonight she and her sister Kylie, who is a special guest on tonight’s finale, are planning to take revenge. A source said: “Until now, Dannii has been very gracious. She has taken Sharon’s bitchy comments on the chin and refused to enter into a public slanging match.

“But when Sharon went on TV and basically likened Dannii’s face to her arse, that was the last straw. She was hurt and upset.

“Her sister Kylie also watched the show and thinks Sharon is well out of order.

“They are all due to face one another – backstage and in front of the cameras – tonight for the finale, so expect fireworks. You don’t mess with Team Minogue!”

Sharon sparked outrage with her vicious comments on Thursday’s Graham Norton Show on BBC2.

First, she claimed Dannii had been hired for the ITV talent show “for her looks rather than her contribution to the music industry”.

She then pulled off a cruel stunt when American actor David Boreanaz, 38, a fellow guest, said he did not know who Dannii was and asked Sharon to show him a picture of her.

She bent over and showed him her bum, before collapsing with laughter and screaming: “I am going to get into so much trouble for this. Well... f*** ’em!”

This latest in a string of insults has devastated Dannii, who was brought into the show this year as a new judge and has two acts in the final. She was said to have been left almost in tears.

Her sister Kylie was just as angry.

A pal said: “Sharon used to be Queen Bee, but she’s had a mighty fall from grace and has been acting like a bitter old woman.

“Her career is washed up. Surely her days on the show are numbered.” However, we can reveal that show boss Simon Cowell, 48, has invited Sharon back on the programme next year – but has cut her down to size.

Fed up with her antics, he is planning to slash her fee from £1million to just £250,000, making her the lowest-paid judge.

But Cowell knows gobby Sharon will accept the offer, because she needs X Factor more than it needs her. Without X Factor, she would not be on TV.

Meanwhile, flu-ridden Cowell is facing a race against time to recover in time for tonight’s special.

The music boss was struck down earlier in the week and even had to miss out on a press conference on Wednesday with his act, Same Difference, because he was so ill.

Now he is desperately hoping he will be fit to see Same Difference slug it out with Dannii’s two acts – Rhydian Roberts, 24, and Leon Jackson, 18 – for the prized £1m record deal.

Cowell’s girlfriend Terri Seymour, 33, has been playing nurse to TV’s Mr Nasty by giving him endless mugs of hot lemon and honey.