Rihanna likes being the bad girl, but she’s more than willing to share her whips and chains, especially when it comes to playing with her fellow sex kitten, Britney Spears.  Let’s just hope they disinfect those toys between usage.

As the two breathlessly  tweeted last night, they have paired together for a remix of Rihanna’s “S&M,” the original of which sits at No. 2 on the Billboard Hot 100 right now. Hear their new version here.

The remix is the exact same musical bed as the current radio version, so it’s not a remix technically, instead they’ve turned it into a duet. The opening is now Spears singing the “C’mon, c’mon” part before Ri Ri sings the first verse as we’ve come to expect. Then Spears sings that verse about “gag and bound me.”  Oddly, she’s got a few years on Rihanna and playing the enchantress is nothing new for her, but she sounds so much more innocent than Rihanna here in her little, slight nasally coo of a voice. “S&M” features one of Rihanna’s strongest vocals so Spears has to bring her best game if she’s really singing instead of doing her talky-thing.

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They duet together on the chorus and then Spears throws in some trademark Britney sounds at the end, that, for lack of a better word,  reminds me of something that one of the creatures from  "Gremlins" would make, but are so identifiably her.

So why did they do this? To get all of us to write about it and to figure out some place they can make a VERY SPECIAL EVENT of performing it together and perhaps to do a video... they can’t let Lady Gaga and Beyonce have all the fun with “Telephone,” can they?

I have no idea if Spears and Rihanna have ever met, but it seems like Rihanna is very open to having fun and making music with whomever she wants: witness her appearance on last week’s Academy of Country Music Awards with Sugarland’s Jennifer Nettles on “California King Bed.”

But, as Hitfix editor Gregory Ellwood just said to me, why not do a brand new song then? Because they don’t have to. They get just as much press from this, which sounds like Spears just went into a studio for a few minutes, threw down her part and sent it to the producer who stripped Rihanna’s vocals and added in Britney’s and, voila, an instant superstar duet. They can borrow the dog collar that Christina Aguilera sports in the video for “Not Myself Tonight” for the video, although we have a feeling they both have their own already, in assorted colors.

UPDATE: We just checked in with Rihanna's label rep and the new version went to radio today so they are clearly hoping it will put some new juice in the single.