After finishing in sixth place on the ninth series of the show, the teenager took some time away from the limelight to work on her debut album, which produced the amazing lead single 'Ghost'.
And it's clear Simon is very proud of his former contestant.
"I don't want to sound biased, but I think Ella Henderson is a really good example of how an artist and a show can work really well together, because we could have released her music in six months. We waited for two years, and she came sixth on the show.
"She represents everything that's great about this country, about the show, and how the label can help someone become a big, big star. I'm really proud of what she's achieved, and she's a great ambassador for the show."
But while he has nothing but praise for Ella, X Factor mogul Simon did have a word of warning on what he DOESN'T want to see from contestants.
"I think it's normally a boy band that's been put together by a manager, and told what to wear, what to say, they all come running in and everything they say is scripted, and they pretend to laugh at each other's jokes," he told the official X Factor website.
"I hate that. I'd rather find something much more raw – like we had with One Direction. We had five talented guys, we never once said 'wear this, say this, do this' – they had that relationship."
X Factor returns Saturday, 30 August on ITV1.
Watch the official X Factor 2014 trailer below:
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