Rihanna showing up at this year's Grammy Awards

Rihanna showing up at this year's Grammy Awards: The lineup of performers who will be appearing at this year's Grammy Awards promises to be one of the biggest of all time, and earlier this week the night got just a little more epic with the additions of Justin Bieber, Usher, Muse, Bruno Mars, Janelle Monae, Lady Antebellum, B.o.B and Jaden Smith. That giant list augments the already-booked