The X-Factor Twitter account have just posted this confirmation in the last few minutes. They had posted earlier simply saying 'Hello', But if you didn't believe us before, then here you go..
Looks like Adele is performing on The X Factor final this weekend. In the last few minutes - the official account for the show simply tweeted 'Hello'.
<blockquote class="twitter-tweet" lang="en"><p lang="en" dir="ltr">Hello.</p>— The X Factor (@TheXFactor) <a href="https://twitter.com/TheXFactor/status/674922884859588608">December 10, 2015</a></blockquote>
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A source close to Simon Cowell told The Sun that everybody is thrilled. One Direction, Coldplay, Little Mix, Leona Lewis and Fleur East will also perform.