Simon Cowell has revealed that Louis Walsh has the biggest backstage rider which includes toys and a pedigree puppy.

The duo have been joined by celebrity judges Nicole Scherzinger, Katy Perry and Pixie Lott on the latest X Factor series, but the music mogul joked that the Irish star trumps them all when it comes to diva-dom.

“Louis is the biggest diva I’ve ever worked with. He is so demanding it’s unbelievable,” he told X magazine.

“His rider for when he comes on the show includes things like a puppy, a pedigree puppy. He requires certain drinks, specific foods. He even has to have toys to play with. It’s the biggest list of demands I’ve ever seen.”

Simon told how Louis made a beeline for former Pussycat Doll Nicole during her appearance on The X Factor.

“Louis around Nicole was just like a little puppy who’s got their first toy to play with and won’t leave it alone. He just kept looking at her. Wherever she went he just stared at her,” he said.

“At lunchtime he was running around getting her things to eat and drink. He even made her fish and chips. He was actually cooking for her! If he could have literally laid down on her lap he would have.

“We had to intervene a couple of times just to tell him to leave her alone. I think Nicole was amused, but the two of them did get on very well, very quickly.”