Appearing on ITV's This Morning, the 16-year-old said: "The whole thing was just overwhelming and the reaction I got was totally unexpected - I'm still trying to find a way of accepting it all, all the compliments that I've been given."
On Saturday, the student from Tetney in Lincolnshire told the judges she had been performing for her grandfather since she was a toddler, before stunning them all with an emotional song written for him after his death.
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Ella Henderson and Caroline Flack on This Morning
Speaking from the This Morning sofa about the experience, Ella said: "The whole day is a waiting game to give that two-minute performance - fifty percent of me was so excited, and the other side of me was really shaky and stuff, but once I was up there and I realised that these four judges are human beings and they are just going to give me honest feedback. I was kind of relieved about that. But I was so overwhelmed hearing the applause and stuff from the audience."
She added: "It was a tough choice to do my own song, but I thought, the rules have changed this year and for that reason I will put it out there - especially with Gary Barlow there, I really wanted to see what his opinion was on it because he's a songwriter himself and I really look up to him."
Caroline said: "It's odd because I spoke to her about two minutes before she went on stage and she was very happy singing a Pink song... and I can confirm you do get given five song options to sing - no one tells you want to sing. She gave the second song, she obviously didn't cut it, and people get knocked back all the time and you don't react like that."
X Factor 2012 Episode 1(01 of33)
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Alexander, or should that be Rod Stewart? (credit:ITV)