Dermot O’Leary has said that even the “most seasoned” stars who appeared on The X Factor: Celebrity were “terrified” by the challenge of singing for the judges.
Fifteen celebrities have signed up for the spin-off series, including BBC journalist Martin Bashir and former The Only Way Is Essex star Megan McKenna.
O’Leary, who has presented nearly every series of The X Factor since 2007, said viewers should not underestimate how tough conditions were during the show’s pre-recorded first stage.
The celebrities were challenged to sing for the judges and a panel of industry veterans at Simon Cowell’s home in Malibu, California.
Diane Warren, who has worked with stars such as Lady Gaga and Beyonce, and David Foster, who counts Madonna and Rod Stewart among his collaborators, featured on the all-star panel.
The celebrity hopefuls were battling it out to secure a place in the live shows in London and ultimately win a record deal.
O’Leary said: “This is the first time they’ve auditioned and I think you can never underestimate that.
“With the regular show it’s progress, it’s rooms, arenas, bootcamps, six chair challenge, all these kind of things that are deliberately there to test them, and to see how many strings they’ve got.
“With these guys, yeah sure, they have experience on the telly but even the most seasoned performers walked out on that stage and told me afterwards they were terrified.
“You walk out suddenly, there’s a hundred people staring back at you, and they know there are a hundred people who work in an industry like Diane Warren, Randy Jackson and David Foster, it’s intense.”
The TV star also admitted that he was left scratching his head over Bashir and talk show host Ricki Lake’s place on the line-up.
Asked who he had been most excited to see, he replied: “Oh, it has to be Ricki Lake. More than anything.
“Ricki Lake and Martin Bashir, they were the two that kind of left you scratching your head thinking: ‘Wow we’ve got some really interesting people on our hands here’.
O’Leary also singled out reality TV regular McKenna, who has forged a career as a country singer since departing Towie.
“I’m really impressed with Megan,” he said.
“She seems like a really lovely, down-to-earth, humble girl.
“It’s great for the show that here’s someone who applied twice, didn’t make it, and now she’s back as a celebrity.
“She knows she wants to be an artist.”
The X Factor: Celebrity will debut on ITV on October 12.
