The Girls Aloud beauty spent over three hours holed up in Simon's Los Angeles mansion on Wednesday, according to The Mirror.
And the secret meeting has sparked rumours that Chezza will be back on the reality TV show's panel.
It's no secret that the series has struggled to pick up the viewers that it's had in past seasons - and Cheryl could prove Simon's secret weapon.
The meeting comes 18 months after he unceremoniously dropped her from the US version of the show - prompting Cheryl to send him a string of expletive-filled texts telling him exactly where to go.
She reignited the feud a few months ago when she agreed to do the Judges Houses stage of the competition and spent the weekend helping current judge Gary Barlow - but after Simon sent her a welcome back message on Twitter, she slammed his advances.
She said: "I saw Simon's tweet. I'm not doing this for him. I'm doing it for Gary. He's my friend and he asked me to do it."
Although Cheryl has said that she will never work with Simon again, this meeting could pave the way for future conversations about her return to 'The X Factor'. Watch this space.