Photo: Rihanna uploads unclad sexy bum from new video shoot!

The 25-year-old posted an extremely saucy close-up of her perfectly toned bare behind, with nothing but a thong covering it, from the set of her Pour It Up clip. 

And given her ex Chris Brown has once again been spending time with her love rival Karrueche Tran, the picture might also have also been aimed at him. 
This babe is not showing any signs of slowing down. Hit or miss?