The 27-year-old star is rumoured to be a judge on the US version of The X Factor when it launches next year and it is claimed she's planning to start a new life in the States.
However sources close to the star say she wants to lose around 9lbs to try and fit in.
A pal said to UK's Now magazine: "Making it in the US will be stressful and she's overwrought. She knows how harsh US audiences and tabloids can be, so she wants to get it right.
"She's seen what happened to Britney Spears with all the scrutiny over her weight and personal life and Cheryl's determined to keep her private life private and focus on work."