Following Kelly Rowland's exit from the ITV1 show and Dannii Minogue's snubbing of a return to the panel, there is still a vacant spot on the ITV1 reality series.
Geri Halliwell, Robbie Williams and Rod Stewart are reportedly among the guests who will fill in during the audition rounds across the summer, but a full-time judge will be needed by the time Judges' Houses is filmed later in the year.
According to the Daily Star, Ora and Lavigne have joined Alicia Keys as possible full-time judges.
Ora has been No.1 in the UK charts for two weeks, while Lavigne was linked to a spot on the US X Factor panel.
The X Factor's first filmed auditions start in Liverpool tomorrow. Halliwell is the first guest judge, who will join Gary Barlow, Tulisa Contostavlos and Louis Walsh on the UK tour.