Osbourne returns to X Factor panel
Sharon, last on the show as a judge six years ago, had been widely expected to return after it emerged she had been in negotiation with programme chiefs. She said she "couldn't be happier" about her comeback.
The line-up announcement means show boss Simon Cowell will be absent for a third year. His departure coincided with a ratings tumble for the show which was last year regularly beaten by BBC One rival Strictly Come Dancing on Saturday nights.
Sharon is reported to have been offered more than £1 million for her return to the panel. Viewers last year saw her briefly make an appearance on the show at the judges' houses stage of the contest.
Sharon said: "I couldn't be happier about coming back for the 10th anniversary of X Factor. I can't wait to give Gary Barlow a big hug, sit next to the gorgeous Nicole, and of course throw water on dear Louis. Yay!"
Simon said: "Three words I never thought I'd say - welcome back Sharon."
Auditions for the next series begin early next month so the panellists had to be in place by then.
In change to the audition process this year, the hopeful acts will face the judges close-up in an intimate audition room. If they get though that stage they will then have to perform once again in an arena to prove they can also impress an audience before they can go through to the next stage.
The auditions in front of judges begin on June 4 in Glasgow, and the arena stage of the process will begin in July.