Schoolgirl Ella, who sings her own song about the death of her grandfather Bill, penned the words when she was 13.
The Lincolnshire contestant wows all four judges at the Manchester audition, including guest panellist Mel B.
The Spice Girls singer commented first: "Whoever, or whatever, you wrote that song about, those words, I'm sure, hit a chord with everyone.
"Your songwriting is so clever. It made me go into my own little world, and go, 'Oh my God' - I felt like that at one point, and that's hard to do as a songwriter.
"And when you sang it, you just made me believe every single word, I was right there with you. What we just witnessed was incredible, absolutely incredible."
Copyright: ITV Thames TVLouis Walsh then said: "It's hard to believe that you're only 16, that was a brilliant audition, absolutely brilliant, you're a class act."
Gary Barlow gushed: "That performance was absolutely out of this world, it really was. That was really something special, thank you very much for that."
Finally, Tulisa Contostavlos stated: "There's so many good things I could sit here and say about you, I could go on and on - the list is endless, but the one thing is that you are the one person that I personally go, 'I really want to mentor, I really do'. I see something so special in you, there's just a spark, you're just a star.
The X Factor launches tonight (Saturday, August 18) from 8pm on ITV1.