The Girls Aloud singer has spent the past few days partying hard to mark her 27th birthday and one friend told the Daily Mail she has “seriously been letting her hair down”.
That meant Cheryl was feeling a little fragile when she arrived to judge the hopefuls at the auditions and she received little sympathy from her boss.
Simon Cowell even pointed out Cheryl’s condition to the audience and aspiring singers.
“She might get a bit sulky and tired if you’re not nice to her. She’s got the disease going around called ‘hangover’. You need to be gentle – she doesn’t want too much noise,” the X Factor supremo joked.
Cheryl, who clearly enjoyed working with guest judge Pixie Lott, had to endure barracking from Simon throughout the day, but managed to take it in good humour.