Cheryl Fernandez-Versini and Louis Walsh's 'X Factor' rivalry has become "toxic".
The returning judge has clashed with her co-star repeatedly while filming for the new series, and it is said his claims she isn't fit to be on the show have left her infuriated.
An insider told The Sun newspaper: "The atmosphere has become toxic - she hates him with a real passion and it shows.
"It's no secret that Cheryl didn't want Louis on the panel, but since then he has been lording his victory and takes every opportunity to knock her.
"On the panel he has repeatedly slapped her down, and she has given him some poisonous stares in return. If looks could kill, Luis would be a dead man."
According to reports, the pair are being kept apart when they are not filming to stop the rivalry going too far.
The source added: "The tension between them became painfully obvious when they clashed at Boot Camp.
"They made Dannii Minogue and Sharon Osbourne look like best pals.
"This is a pressure cooker and it's only a matter of time before someone explodes."
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