The music mogul dropped the bombshell on Craig Doyle Live, where he also teased details of the upcoming ninth UK series.
Reports have been speculating already about whether the full line-up of Gary Barlow, Tulisa Contostavlos, Kelly Rowland and Walsh will be back, along with host Dermot O'Leary.
He said: "I don't know. OK, I think I'll be back, I think Gary will be back. I think Tulisa will be back. Dermot's definitely back!
"I'm not sure about Kelly. I'm not sure. No-one is contracted guys. I loved Nicole Scherzinger."
But when asked if he was implying Scherzinger would be joining the UK show, he said: "No, honestly not".
Of the US version, he teased: "I was out with Simon Cowell during the week, he's in London. You know like you do and I know he is talking to Britney. He's definitely talking to Britney to do his American show. Absolutely true!"
Britney Spears on tour