The 'So Macho' singer, who starred in last year's I'm a Celebrity, claimed that Cowell is hoping his presence will help the show overtake Strictly Come Dancing in the ratings.
"Simon plans to be back, along with last year's judges Gary Barlow, Tulisa Contostavlos, Kelly Rowland and Louis Walsh," she told Closer.
Referring to last year's ratings defeats to BBC rival Strictly Come Dancing, Sinitta added: "He likes winning, so he's set on beating Strictly in the ratings."
However, the 43-year-old believes that the Syco boss will not commit to the show in the long term "because he's so busy".
Cowell recently revealed that he is thinking of replacing the X Factor format with something "new" in 2013.
The music mogul had previously outlined his desire to renew the contracts of the 2011 judging panel.