X Factor final hit by crisis

The X Factor final was thrown into chaos today after Rihanna pulled out at the last minute.

The US star was to perform her hit Umbrella with boyband JLS.

Contestants were left having to swap their celebrity partners around only hours before tomor row night's show.

Crash withdrawl: Rihanna will not be performing

Several have been reduced to tears by the stress of late-night rehearsals as organisers try to scramble their routines together. Alexandra Burke will now team up with Beyoncé, JLS will perform a group duet with Westlife and Eoghan Quigg will sing with Boyzone.

Insiders say Rihanna pulled out to rehearse for her US tour and it is believed the 20-year-old singer wanted to use judge Simon Cowell's private green room as her dressing room.

An insider said: "It has been complete chaos. The organisation which is needed to orchestrate three international acts and the finals is huge - especially as it's all live on prime-time TV.

"The show's bosses are furious that Rihanna has given them so little time to reorganise everything, and they feel rehearsing for her US tour is quite a weak excuse.

"Brian Friedman has had to re-choreograph many of the dance routines, and the added rehearsals have really taken their toll on the contestants.

"Rihanna's people only told them yesterday morning, giving them just two days to reorganise."

X Factor bosses had already been taken aback by a list of demands from Rihanna that even surpassed those of Britney Spears two weeks ago.

Her huge entourage had demanded that metal detectors were set up at entrances to the studios, and no one was to speak to the singer unless spoken to first.

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Like Mariah Carey and Britney before her, Rihanna was to have sole use of Cowell's green room as her dressing room.

Her rider also included the bizarre request of hard-boiled eggs to be available for her throughout the day at any time.

A spokeswoman for Rihanna denied she had pulled out at the last minute, adding: "She was never confirmed for the X Factor. She was only scheduled to fly in for the Jingle Bell Ball and the Royal Variety Performance and was always going to be flying back to the US today."

The latest odds from bookmaker Ladbrokes put Alexandra as the favourite at 8/13, JLS at 9/4 and Eoghan Quigg at 9/2.