Britney Spears isn't duetting with X Factor USA act Carly Rose Sonenclar, Demi Lovato IS PERFORMING. WTF!

We were pretty sure that having sat on the X Factor USA panel all this time we'd be treated to a Britney Spears duet in the final.

Britney Spears won't be performing with her act. Copyright [Splash]

But unlike the UK show where mentor Nicole Scherzinger took to the stage, the American singer WON'T be collaborating with her act Carly Rose Sonenclar when she competes for the 2012 title.

The duets were announced yesterday at a press conference where it was revealed it will be country singer LeAnn Rimes who performs with Carly Rose, instead of Britney.

Carly said at the press conference: "LeAnn Rimes will be singing with me. I'm really exciting because I think that she's amazing and her voice is really special so I'm excited."

Britney's act Carly Rose will be duetting with LeAnn Rimes instead. Copyright [Splash]

And Britney posted on Twitter: "Absolutely huge duet planned for @CarlyRoseMusic on Wednesday. I'll let her tell u who it's with" with a link to the video of the announcement.

But she's clearly got massive faith in her act to go all the way as she tweeted: "Spending the day with the one & only @CarlyRoseMusic. I'm telling y'all... this girl is COMING for the win this week."

Fellow female judge Demi Lovato WILL be hitting the stage - as SiCo confirmed that she will be pairing up with his group act Fifth Harmony.

Despite the fact that teen star Demi has no act in the final three (and the fact that there is no love lost between her and Simon) she's been asked by Mr X Factor to duet with his girlband.

Simon Cowell announced the news at a press conference for the finale saying: "Kinda irritating to say, the person we've decided to duet with is Demi Lovato."

Simon Cowell's group Fifth Harmony will be duetting with Demi Lovato. Copyright [Splash]

And LA Reid's act Tate Stevens will be hitting the stage with American country group Little Big Town.

If Tate does win it for LA it will be his last victory on the show, after he announced last week he won't be coming back next year.

And with LA gone, it is also reported that show bosses are worried that they will not be able to afford Britney Spears for the next season.

After disappointing ratings, producers are believed to be being forced to cut costs and Britney Spears does not come cheap.

A source said: "Producers were hoping to pull in between 15-20 million viewers but the show hasn't reached those expectations".

"Those numbers add up to cost cutting and Britney will be expendable. Producers will be looking to spend less on the production of the show, including the judges' salaries."

"Britney is on a $15 million contract, which is absurd given that there's been no huge surge in the ratings."

[Related story: X Factor USA judge LA Reid won't be coming back next year]

[Related article: Britney Spears' contestant voted off X Factor]

[Related article: Britney gets her boobs and her legs out]

Demi Lovato wants to sing with Britney SpearsDemi Lovato would love to collaborate with Britney Spears on a new song.