Prison officer Sam won the recording contract prize and chance to support Beyoncé on tour after receiving more than one million votes to beat Nicholas McDonald during Sunday night's finale (15 December).
She will release the Demi Lovato smash 'Skyscraper' as her winner's single.
Simon tweeted a message to the latest X Factor star after the show, writing: "Congratulations Sam. Well deserved. And I love your version of skyscraper. Happy Xmas. Simon (sic)."
The music mogul left his spot on the UK judging panel to launch X Factor in America, where he is currently nearing the end of their third season, but has remained heavily involved in the UK version.
Interestingly, he serves as a judge in the US alongside former Disney star Demi. Inspiration for Sam's winner's song, perhaps?
Sam, 36, could very well be performing 'Skyscraper' in the US soon if recent reports are to be believed. It's been claimed that Sharon Osbourne, who mentored Sam, is eager to launch her in America and wants her to appear on her US chatshow The Talk.
In the meantime, however, it seems Sam still needs to let the news sink in.
During an appearance on Xtra Factor after the results show she admitted she was still in a daze, describing herself as a "deer in headlights." She didn't even know she had a music video coming for her song!
But even though she's the X Factor winner, Sam admitted she had a quiet night planned. "I know there is a little party going on but I have to be up early. I'll probably have a cup of tea... I'm not very rock 'n' roll!"
The X Factor final in pictures:
Copyright: Rex Features Tom Dymond / Thames