Rihanna's 'S&M' remix featuring Britney Spears is No. 1 on iTunes, as the two pop princesses trade lyrics about whips, chains and other sexy stuff! RiRi called into New York City's pop radio station NOW FM recently and immediately shut down host Lil Cee when he questioned whether or not Brit Brit brought her "A" game to the 'S&M' party, insinuating that Brit sounds nasally and that she phoned her vocals in nonchalantly. RiRi was quick to defend Spears, pointing out that the song is numero uno and you can't really argue with that cold, hard fact.

"That's their opinion," Rihanna says when Lil Cee mentions that some fans aren't digging what Brit did with the song. "It's dynamic and it's No. 1 on iTunes right now. It doesn't matter, you know? People will always have their opinion and that's fine." RiRi says that she is confident that Brit did her very best, and that she soars to the appropriate heights, saying, "It's a high song to sing. It's really high, in a really high register. I thought she did incredible."

Rihanna also reveals how the partnership came to be, saying, "I always wanted to work with her. It would be so unexpected for two artists in the same genre to collaborate and she had never been featured on anyone's record … Ever. She was enthusiastic, loved the idea and went right into the studio!" How's that for phoning it in? Sounds like Brit was stoked to work with the Barbadian songstress from the way RiRi tells the story.

Lil Cee also asks the 'Only Girl in the World' to engage in a couple of rapid fire questions. In case you have burning curiosities about things like Rihanna's computer preferences (she's a MAC girl, not a PC girl), check out the interview audio clip below. Ri says she is single, has never stolen candy from a store and that a "nice smile [and] nice facial hair" are the first things that make a potential suitor attractive to her.

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