According to Media Takeout, Cowell is 'desperate' to secure the former Destiny's Child singer in a bid to boost the show's ratings, following the departure of judges Paula Abdul and Nicole Scherzinger.
A source told the website: "[Cowell] wants a big name female star on the panel. Mariah [Carey] is good, but she's not that hot today.
"He wants Beyoncé because that would immediately give him the bounce needed to beat American Idol."
Separate sources have since told E! Online that the rumours are 'unlikely to be true' with the $500million sum being "especially crazy."
Cowell has previously commented on the axing of Abdul, Scherzinger and host Steve Jones, stating: "I want to say a massive thank you to Paula, Nicole and Steve for being part of The X Factor last year. We had a lot of fun making the show together.
"I'm sure all three are going to have massive success in what they do next, but now is the time to thank them all for everything they did last year."
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