The singer will join Simon Cowell, Louis Walsh and Cheryl Cole for the try-outs, as will Natalie Imbruglia and Pixie Lott.
Imbruglia will be part of the Birmingham auditions on June 13 and June 14.
ITV has already confirmed Dannii Minogue's first temporary replacement - Geri Halliwell - as well as the appointment of Konnie Huq to replace Holly Willoughby as host of The Xtra Factor.
Dermot O'Leary will continue as the main presenter for the series, which will see an extra audition in Dublin. Meanwhile, Minogue - who is due to give birth to her first child next month - will return for the Judges' Houses stage of the competition in the autumn.