Take That frontman Gary, who confirmed he was quitting the show during its 10th series last year, explained that fans will want to see the "chemistry" between Simon and Cheryl on the panel.
Speaking on Alan Carr: Chatty Man, which will air tonight (28 March), Gary said: "The fans are very passionate about that show and I think for the audience they will really enjoy it. I think everyone will be watching to see what the chemistry is like this time.
"Everyone's always talking about it, it's so rating driven that show. One week it's down, one week it's up. You know it's just an incredibly successful show.
"I think they [Simon and Cheryl] will make it more successful coming back to it. I think it's fun to watch, we all love it really. We say we hate it but we love it."
Music mogul Simon announced his return to the show in February, with Girls Aloud star Cheryl confirming her comeback almost a month later.
Speaking about who should join Simon and Cheryl on the judging panel, Gary seemed certain that Louis Walsh will be back for another year, saying: "He's back, he's always back!"
Elsewhere, it's been widely reported that Nicole Scherzinger will not be returning to the show this year. Even though she hasn't actually confirmed it herself, Simon did hint at Nicole's exit last month via a message on Twitter.
"For me, I'd have Nicole back again," Gary continued. "I thought she was a great judge and for all of her contestants she was great. She'd spend all week meeting with them, going to Greggs with them. She really did work really hard."
Speaking about his exit, Gary added: "Do you know I had three brilliant years, especially last year. Last year was a hoot from the word go and it was just time to go.
"Three years is just long enough. I didn't over stay my welcome, I just did it and enjoyed it and I can move on now."
Watch Gary talk about The X Factor and his music plans with Take That on Alan Carr: Chatty Man tonight at 10pm on Channel 4.
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Watch Gary's music video for 'Let Me Go' below: