The US star joined Nicole in Dubai to film their latest section of the show, which will air on ITV1 later this month.
Together with Nicole, Ne-Yo helped to whittle down the acts in the boys category ahead of the live finals in October.
Speaking at the Staples Center in Los Angeles ahead of tonight's MTV Video Music Awards, Ne-Yo said: "I'm honest.
"I'm not going to be as mean as say Simon Cowell but I can't sugarcoat it when it comes to music, that's one of the few things that I can speak 100 per cent passionately and honestly about."
He told BANG! Showbiz: "I've heard the guys and there's some serious talent in that group. I don't envy Nicole making the decision she had to make."
The judges' houses will continue to be filmed over the next few weeks.
[tag]Gary Barlow[/tag] is set to stay in London and will be joined with Robbie Williams to decide which acts in his category make the live shows.
[tag]Louis Walsh[/tag] previously joined forces with Sharon Osbourne in Las Vegas while [tag]Tulisa Contostavlos[/tag] is currently visiting St Lucia with UK star Tinie Tempah.
This year twelve acts will make it through to the final live shows, which are due to start in October.
The X Factor continues next Saturday night on ITV1. The judges' houses section will air next month.