There's a bitter fight for the 26-year-old between top US record label Interscope and Simon Cowell, who wants to oversee her American move.
It's great news for her career, but bad news for her marriage to Ashley, 28, which is sure to come under increasing pressure due to her work demands.
'Simon wants to sign Cheryl up lock, stock and barrel so he can control her music and TV activities in the US and make her the biggest female talent on the planet,' says our source.
'But there's no way Ashley will follow Cheryl. He isn't about to do a David Beckham and play football in the States - he's at the peak of his career and wants to stay at Chelsea. This would cause tension in even the most stable relationship.
'Ashley isn't happy - he thinks she's being selfish - but Cheryl's career is her priority. There's a new hard edge to her, which shows how ambitious she is.'
Cheryl has even seen a voice coach to help tone down her strong Geordie accent. Our source says: 'They have nearly a year to fix any problems with her accent if they don't launch the US X Factor until autumn.'
It's inconceivable that Simon wouldn't give Cheryl a job on the show after she increased ratings on the UK version by six million viewers.
But that could spell trouble for Ashley. Our source adds: 'It's a shame he won't be by her side, but Ashley's six or seven years away from retiring. Cheryl's career can't wait, though. It has to be now or never.'
See the full story about Cheryl and Ashley Cole in Now magazine dated 16 December 2009 - out now
Where to next?
- What really going on with Cheryl and Ash's relationship?
- See Cheryl's transformation!
- Latest celeb pics!