Rihanna Twerkin' Off To Drake Song

7/3/2013 9:50 AM PDT

Rihanna -- Twerkin' Off to Drake Song

The following video of a twerkin' Rihanna will probably upset Chris Brown for two reasons:

1) It's sexy ... and she's reportedly cut him off from tappin' that ass.
2) She's twerkin to a Drake song ... Chris Brown's mortal enemy.

The footage was posted by one of Ri's friends -- showing the pop star gettin' down to A$AP Rocky's song "F**kin' Problems" -- which features Drake.

During the clip that was posted, Rihanna shakes her ass during Drake's verse.

It seems to be a thinly veiled dig at Chris -- considering he and Drake hate each other so much, they brawled at W.i.P. nightclub in NYC last year.