With Rihanna watching, 'X Factor' contestant Phillip Lomax attempted to give her hit 'Please Don't Stop the Music' some crooner style. It was a nerve wracking experience for Lomax -- who's part of judge L.A. Reid's boys team on the Fox show -- but the 22-year-old charmed the hip-hop beauty.

"It was very charming … he was very sure," she said after Lomax walked offstage. He wasn't the only contestant to tackle a Rihanna hit, although he was the only one to have to perform in front of her.

Earlier on Thursday night, the Brewer Boys sang a pop-country version of 'Only Girl in the World.' The teen brothers put their own unique stamp on the challenging song, but it wasn't clear how judge Paula Abdul and guest judge Pharrell felt about them.

Enrique Iglesias helped judge Nicole Scherzinger rate 34-year-old James Kenny's version of Rihanna's 'Russian Roulette.' Iglesias admitted it was a difficult song for a man to sing, but then shared Scherzinger's opinion that Kenny could be a rock star. The waiter/husband/father from Hollywood, Calif. turned in an impassioned performance of the song.

All contestants will learn their fate after Sunday's episode of 'X Factor.' Only 16 of the remaining 32 contestants will move on to next week's live rounds.

Watch Phillip Lomax Sing Rihanna's 'Please Don't Stop the Music' on 'X Factor'

Watch the Brewer Boys Sing Rihanna's 'Only Girl in the World' on 'X Factor'

Listen to James Kenny Perform Rihanna's 'Russian Roulette' on 'X Factor'