When Rihanna isn't booty clapping to Trey Songz, she's singing on "American Idol."
Like last night, when she appeared on the show to perform "California King Bed," a ballad from her LOUD LP.
She even posed for a picture with Idol judge Jennifer Lopez, who was recently named "Most Beautiful Person In The World" by PEOPLE mag.
Side by side, who's hotter, J-Lo or Rihanna?
Later in the evening, RiRi went to Osteria Mozza in LA for dinner.
Devil in a red dress!