And not for the first time.
The former Voice UK coach has said she's turned down the music mogul before too, branding the show and it's judges BULLIES.
“He has offered me X Factor twice. I think the show’s been a major success and loads of amazing acts have come out of it but I can’t handle the whole taking the p*** out of people," Jessie said this week. “I can’t sit and watch them putting people through for TV amusement and I said that to Simon’s face when I sat with him.
“I said, ‘I appreciate you as a businessman but I’m not a bully — and it’s bullying.’”
Jessie praised X Factor's BBC rival The Voice, which Jessie J quit last year, because all of its panel were actually singers.
She told The Sun newspaper today: “The biggest difference is the coaches on The Voice — we are doing it, we are current artists.
"I don’t know how I’d feel taking advice from someone who hasn’t lived through what I’ve done."
The Bang Bang singer quipped: "“Obviously Cheryl is an artist but Louis? His last album was great..."
She added: "If Simon was like, ‘I thought that was awful,’ I’d say, ‘Come and sing it better then.’"
Jessie was replaced by Kylie Minogue on The Voice UK but she's now also quit.
Rita Ora will join the show alongside Will.i.am, Ricky Wilson and Sir Tom Jones for next year's fourth run.