Jess appeared on the ITV talent show for the Judges' Houses stage of the competition where she joined judge Cheryl Fernandez-Versini as a special guest to help whittle down her groups category.
Chart-topping singer and songwriter Jess told Free Radio Live's Adam Wilbourn that being on the show herself made her see it in a "different light".
Jess said: "When people are going on consistently about 'Oh they can't sing' etc, it's not just actually about the voice, it's about how entertaining someone is and whether you can see someone actually doing well and selling out tickets to a show. That's what it's about."
In fact, Jess has said that being on the show has changed how she watches it as a viewer.
"I'd watch the show sometimes and be like 'Why the hell have they chosen that person, they can't sing', but actually it's not about that, it's about the entertainment," she said. "So actually it showed me a different side to the X Factor.
"I was so nervous for them (the contestants), what a horrible situation for them to be in you know! Me and Cheryl sitting there, oh man, that's just…!"
Cheryl picked Reggie 'N' Bollie, 4th Impact and Alien Uncovered as her final three acts. Now only Reggie 'N' Bollie remain in the competition.
Try Reveal's digital edition on iPhone & iPad. Subscribe now & never miss an issue!
X Factor's most shocking moments: