Britney Spears' $15 million X Factor USA contract wasn't renewed because she was "very uncomfortable" on the show.
The show's boss Simon Cowell has admitted he didn't realise that the Scream & Shout singer is not a big talker and confirmed it was the main reason he decided to replace her on the judging panel this year after just one season.
The 55-year-old British star told The Ellen DeGeneres Show in a new interview that will air in the U.S. on Tuesday: "I didn't realise that! I kind of booked someone who couldn't talk, which is a bit of a problem when you want someone to judge."
He added: "She wasn't comfortable being negative, she didn't like it when the contestants spoke back to her, so she was just uncomfortable. I liked her. So we decided to change it this year and I thought I'll work with three girls because I like working with girls."
Simon also confessed that he only asked Britney, 31, to be a judge as he got caught up in competing with American Idol and The Voice USA to feature high profile judges such as Jennifer Lopez and Christina Aguilera.
He said: "I think if I'm being honest with you, Ellen, there was a time I think everyone was trying to up themselves in terms of who could find the biggest known star to be on a panel. And in terms of a pop singer? Jennifer Lopez and the other one on The Voice... I can't remember. Blondie. Christina. And we said, 'We'll take Britney'. She was fine, but I think she found it very uncomfortable."
Britney previously claimed she decided to leave the show to focus on her music career.
She said in a statement in January: "I've made the very difficult decision not to return for another season. I've had an incredible time doing the show and I love the other judges and I am so proud of my teens, but it's time for me to get back in the studio."
Kelly Rowland and Paulina Rubio have joined Simon and Demi Lovato on the judging panel of this year's series.
- BANG! Showbiz