Under Sharon's guidance, former prison officer Sam became the first ever Overs category act to win the ITV competition when she triumphed over teenager Nicholas McDonald on Sunday (15 December).
It was a particularly special night for Sharon as it marked her last day as an X Factor judge. When she returned to the panel earlier this year she made clear it was just for one series.
Kelly tweeted: "OMG @SamBaileyREAL won I'm so happy I'm crying!!!!!!! @MrsSOsbourne what a perfect ending to your #XfactorUK journey! I love you both xoxo."
She also said: "Now you guys truly got to see how much my mum loves and believes in @SamBaileyREAL!"
Meanwhile, Jack, who was watching with his baby daughter Pearl, added: "F**k yeah!!!!!!! Go @SamBaileyREAL #teamsharon.
"I'm so happy for @MrsSOsbourne and @SamBaileyREAL ! Yay yay yay!!!!"
Sharon was obviously thrilled by the success of the night, telling her Twitter followers: "Thank you everyone who has backed @SamBaileyREAL on @TheXFactor! She couldn't have done it without all of you behind her! #XFactorFinal. I am so blessed to have been a tiny part of @SamBaileyREAL's victory tonight on @TheXFactor. Thank you. #XFactorFinal."
She also made sure to thank viewers for all their support over the series, saying: "Walking out for my last ever @TheXFactor. Thank you all for your love and support for @SamBaileyREAL and me. God Bless you all. Love, Sharon."
Meanwhile, Sam's winner's single, a cover version of the Demi Lovato smash 'Skyscraper', has already shot to the top of the iTunes chart.
The X Factor final in pictures:
Copyright: Rex Features Tom Dymond / Thames