"The X Factor USA" judges - Simon Cowell, Britney Spears and Demi Lovato - have major competition to contend with next season.

Justin Bieber has agreed to become a guest mentor for Antonio "L.A." Reid, the show's fourth judge.

The "Boyfriend" singer filmed a segment for the hit singing competition and reality show at a home in Hollywood Hills on Monday, Aug. 27. As one of the show's guest celebrity mentors, he will assist Reid in choosing singers.

"Away from twitter all day getting this work in. missed my peoples. #BELIEBERS love you. #DirectRelationshipWithMyFans #MUCHLOVE," Bieber tweeted that evening. 

In photos posted on Just Jared, Bieber is shown with Reid filming the "judges' houses" phase of the competition. Sixteen acts have already been narrowed down from the top 32 acts and they will later compete in the show's live episodes, which begin airing in October. 

Reid is responsible for the "Over 25" singers category and reportedly, Bieber's fans, nicknamed Beliebers, have already created buzz online disagreeing with his mentorship for that age group.

Nick Jonas is reportedly working with judge Demi Lovato. The two former Disney stars will work together with contestants ages 12 to 16.

"The X Factor" is searching for undiscovered talent ages 12 years old or over, as solo artists or vocal groups, competing for a chance to win a $5 million recording contract with Syco/Sony Music. 

X Factor USA has a two night premiere on Sept.12 and 13 at 8/7c on Fox.