Cowell is joined by Nicole Scherzinger, Paula Abdul and L.A. Reid on the panel of The X Factor. He enjoys working with all of them, but has come to notice something strange about Scherzinger.
"Paula can be a bit wacky at times, but Nicole wasn't far behind in a fantastically self-centred way - which she wasn't aware of and I found really amusing. Every city we went to, she changed her accent," he told EW.com.
"In New York, she had kind of this Brooklyn thing going on. In Dallas, she was a southern belle."
Cowell and Abdul previously worked together on American Idol, before she left the show. He's enjoying collaborating with her again and believes she's perfect reality TV show material.
While most people are wary of cameras, Abdul forgets they are rolling.
"Within five minutes of when we start filming, she's not aware that the cameras are on anymore and she'll fight with you over something - sometimes important, sometimes not. Kind of like getting an old dog back from the rescue pound," he laughed.
The first trailer for The X Factor premiered in the US earlier this week. Cowell and Abdul are seen sharing a lingering kiss, which has caused a stir.
The music mogul admitted he isn't sure whether he's still engaged to make-up artist Mezhgan Hussainy recently, with the closeness he enjoys with Abdul calling his relationship into further question.
"There is a genuine chemistry between Simon and Paula. They are outrageous flirts," a source told British newspaper The Daily Mirror.
"Simon knows that rumours of a love interest between him and Paula will appeal to X Factor viewers and he is playing up to it. Sometimes they will have on-screen rows but there is a close bond between them so flirting will always follow. I'm sure Mezhgan is not very thrilled."
- AAP