Rihanna on 'The X Factor' - Sneak Peek!

Check out these pics of Rihanna making an appearance on TONIGHT’s The X Factor!

The 23-year-old pop star joined judge L.A. Reid as he coached the boys team.

People reports that Pharrell Williams and Enrique Iglesias will also be making an appearance on the episode, which follows the 32 remaining contestants as they visit the homes of L.A., Simon Cowell, Paula Abdul, and Nicole Scherzinger.

“The acts were totally blown away meeting their mentors at these amazing homes – then it was even more nerve-racking performing for a guest judge,” a source told the mag. “Some of the girls especially were delighted when they saw Enrique and Pharrell. The acts who met Rihanna were totally speechless – who knows how they managed to sing!”

Catch Rihanna and the other celeb guest judges on The X Factor TONIGHT at 8/7c on FOX!

FYI: Rihanna is wearing the signature “Love” ring in pave diamonds by Sydney Evan.