They will join returning host Dermot O'Leary next season. Auditions will begin June 10.
"I'm overjoyed about going back to The X Factor, sitting with Lou. Lou, gorgeous Nicole and naughty Simon. But most of all, I can't wait to meet baby Eric," Osbourne said in a statement, referring to Cowell's young son.
"I can't wait to be back in the United Kingdom and on the show with the best judges sitting alongside me on the panel. I'm excited about discovering, mentoring and winning with an exciting new act this year. And having had winning contestants in the past, Simon knows I will do it," Scherzinger added.
"He'd say otherwise, but I knew Simon missed me last year! I'm delighted to be back on the panel especially beside my two favorite female judges Sharon and Nicole, and I'm looking forward to taking them all back to Dublin this year when we head there for auditions," Walsh remarked.
ITV Director of Television Kevin Lygo stated: "Simon, Sharon, Louis and Nicole -- they're a formidable judging panel by anyone's standards. With Dermot hosting and the return of the audition rooms, there's a lot to look forward to this series, as we welcome back one of our biggest entertainment brands."
The X Factor will return to ITV later this year.