The 'Do It Like A Dude' singer will join N-Dubz star and new judge Tulisa Contostavlos in Greece later this month to help finalise her category for the live shows.
Show boss Simon Cowell, who wanted Jessie J to perform on last year's X Factor final, is said to have intervened to get her involved.
A source told The Sun: "He's keen for her to sing on the show."
Beyoncé will apparently join Kelly Rowland in Miami, while Louis Walsh is said to be livid after Adele, who he'd asked to join him in Barcelona, was replaced with Sinitta as a mentor.
Watch Jessie J's video for 'Who's Laughing Now' below: