Simon Cowell has admitted the reinstatement of the audition room segment on The X Factor has been a "nightmare" and caused him to feel "awkward and uncomfortable" as there is "nowhere to hide".
"I hate it. Personally, I've found it a nightmare. That's probably why people like it so much," the music mogul said ahead of Saturday's launch show.
"You have the public behind you. When [the contestants] come in and they are really bad, there's literally nowhere to hide."
The room auditions were replaced by live auditions in which hopefuls sang in front of the judges and a live audience for several series. In series 10 and 11, both the live and room auditions were used.
Osbourne admitted she had reservations about returning to the show, because she was not sure how the British public felt about her.
The judge, who lives in the United States, will split her time between the UK and Los Angeles, flying back and forth every week, and working with her contestants via Skype.
She has also given fans something to look forward to, as she has hinted that she may throw water on the show once again.
I felt like I had drawn a line in the sand," he said.
"Then I gave myself some time to think about it and I realised I had missed the live shows, I missed the team and I missed being part of a show that's part of the national conversation and culture."
Also returning to the show will be former-Pussycat Doll, Nicole Scherzinger.
The singer defended the judging panel against criticism that it is "too old".
At 38 Scherzinger is the youngest judge, while Cowell is 56, Osbourne is 63, and Walsh is 64.
"I don't think the panel is too old. I mean, you have me and I'm Sch-amaze balls! Then Simon invented this, Mrs O is the queen of rock and roll and Lou Lou has been doing this forever, so I think experience speaks for itself.
"I think it's hard when you're trying to make a new start and discover things, just blossoming and haven't experienced life yourself. You're still trying to figure it out, so how are you going to mentor someone else who hasn't even gone through life enough?"
The new series of the X Factor begins on Saturday and ITV.
Viewers can look forward to acts including a living doll and a woman who stormed into the audition room uninvited.