Katy Perry is one of the four pop stars who will replace Dannii, as she is expecting a baby. Well, who the three others are?
The answer is: Pixie Lott, Natalie Imbruglia and Geri Halliwell! The four of them will make guest appearances along with the usual suspects, Simon Cowell, Cheryl Cole and Louis Walsh, while Dannii will join them when the talent show reaches its boot camp phase! Let's wait and see…