Michael Bublé has admitted that he finds appearing on The X Factor a very scary experience.

“You are about to be judged by 14 million people. It is not the easiest gig in the world,” he told The Sun.

“The atmosphere down there is scary. It’s like the Coliseum in ancient Rome. Everyone’s cheering and booing. It makes what I do seem a piece of cake.”

Speaking about the contestants, he said: “Time will tell if these kids turn out to be karaoke singers or artists. But at the end of the day it’s an entertaining TV show. It’s a soap opera. If an artist comes out of it, then that’s a bonus.”

He also defended Robbie Williams and blasted people’s attack on the Take That sta after his comeback performance on the show.

“People are very quick to jump on a guy and say ‘he’s high’ or, ‘he’s drunk’ but Robbie was getting up on stage for the first time in three years. Give the guy a break,” he said.

“I can seem a bit loose and apparently some people thought I was drunk. So I felt for Robbie. I’m a huge fan of his and would love to do a duet some time.”