The X Factor's longest-running judge Louis Walsh has promised that the inaugural show of the new series is "the best first show ever".
He told ITV This Morning: "I think the talent all round is better" and added that he was particularly excited that original artists have been allowed to enter with their own material.
Here's a sneak preview of the new series:
A lot of attention will also focus on the new judge, Nicole Scherzinger, who has transferred from the American version of the show.
She joins Louis Walsh, Gary Barlow and Tulisa Contostavlos on the judging panel.
Walsh revealed that he has already spent an evening with Nicole to get to know her and described her as "a real rock chick".
One of Walsh's highlights from the new series is a guest appearance by Mel B from the Spice Girls.
She has already appeared as a guest judge during one of the rounds of auditions and, according to Walsh, is "very bold and very funny".
Asked whether he missed Simon Cowell's presence on the show, Walsh said he did but that Cowell still exerts a strong influence.
He said: "He owns the show and he's on the phone to everyone telling them how it could be better".
O'Leary said he thought the competitors in the new series are arriving "with a really strong idea as to who they want to be" instead of expecting the judges to mould them into a particular image.
He also said that the television doesn't get across how hard the competitors work, and that the real work only really starts once the series has finished.
O'Leary, who is getting married to long-term girlfriend Dee Koppang in four weeks, refused to reveal their choice of song for the first dance.
The X Factor is on ITV1 at 7:30pm on Saturday.