Simon Cowell's monster X Factor trailer

Simon Cowell has a giant trailer on the set of US X Factor.

Judge Nicole Scherzinger claims the music mogul who left the UK version of the talent show to concentrate on the new prograM acts like a “diva” behind the scenes, but he sometimes lets her use the toilet in his “phenomenal” mobile home.

“He’s a bit of a diva, I’m not going to lie,” Nicole said. “He’s got one of those huge Will Smith trailers. They’re pretty phenomenal, I like to go and ask if I can use the toilet. He lets me every now and then.”

The former Pussycat Dolls singer admits the 52-year-old executive producer can be very unpredictable on set, but she is “inspired” by his passion for music.

“We’re pretty cool. I teach him a thing or two. He’s like a box of chocolates, you never know what you’re going to get when you come into work,” she added.

“But he’s inspiring. He knows what he wants, he’s very passionate about his work, as am I. I remember when I first worked with him last year in the UK, there was crazy music like We are the Champions.

“I was like, ‘What kind of singing competition is this?’ He said, ‘Nicole, you know how passionate you are about your music? That’s exactly how I am.’ “