Which Rihanna Collaboration Is Your Favorite?

This morning, Rihanna added another A-list collaboration to her lengthy résumé list. After RiRi and Britney Spears announced via Twitter this weekend that they did a remix of the Loud single, "S&M," the song hit the radio and Net. And, inevitably, we began recalling Rihanna's other partners in crime.
But, Brit is hardly the first superstar [...]

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