Sources from the US show say the unkempt singer rolled out of bed and rocked up to a taping without a bra early on in the series, prompting Simon to lay down the dress-code law.
"It was made clear she is expected to be impeccably dressed and made-up for the show. And none of those ragged hair extensions," an on-set source told the New York Post.
X Factor reps have denied reports that Brit was also ordered to sack her stylist, but apparently she's been looking fabulous ever since Simon's style intervention.