Internet rumours, and breast augmentation specialists, suggested the Girls Aloud star had boosted her bust to help win fans in the USA.
The 27-year-old is set to join Simon Cowell on the Stateside version of the X Factor.
But despite her fuller-looking figure her spokesman laughed off the boob job speculation as rubbish.
He said: “Cheryl has not had breast surgery and has made it clear in several interviews she has never had work done and does not intend to.”
The speculation was sparked after decidedly perky-looking photos of Cheryl Cole jogging in Los Angeles were published in Britain's tabloid press.
A senior Harley Street cosmetic surgeon was reported as saying: “Cheryl’s boobs look very different now.
“You can see how rounded and full they seem. To mimic this look, she would have to be wearing a good gel bra.”
Cole has previously commented on boob job rumours saying: “I wouldn’t just come out with big boobs and say: ‘No, I haven’t had an operation!'”