The singer and producer joined Paula Abdul as her guest judge in Santa Barbara, California to judge the remaining eight groups and decide which four to advance to the live performance shows.
© Fox
© WENN
Pharrell Williams
Their decision will be revealed in a special episode of X Factor airing Tuesday, October 18 at 8/7c on Fox when the Top 16 will be announced.
Pharrell said in a video posted to the show's official YouTube account: "You look in the eyes of every last one of those kids and they all want it so bad.
"I look at The X Factor and it really reminds me of what we've always had in our hearts in N.E.R.D. - really not accepting no for an answer and kind of shoving the yes down the throats of the powers that be."
Pharrell was one of three high-profile guest mentors to join X Factor's judges for the Judges' Houses stage of the competition.
Enrique Iglesias joined Nicole Scherzinger to judge the Over 30s in Malibu, while LA Reid invited Rihanna to help him choose between the boys in The Hamptons.
Simon Cowell had hoped to have Mariah Carey join him to hear the girls' performances in France but flight problems caused by Hurricane Irene meant she was unable to travel.
X Factor's winner will secure a $5 million recording contract with Sony Music/Syco and the chance to appear in a Pepsi Super Bowl commercial.
> Digital Spy recaps X Factor Judges' Houses Day 2
> Read Digital Spy's full X Factor headlines
Watch more of Pharrell talking about X Factor below:
