Rihanna's on-stage performances are always pretty racy
Rihanna - virginal in white - greeted a masked Britney wearing a matching black PVC bondage-style body suit adorned with buckles and belts.
The raunchy pair writhed up and down poles before having a pillow fight and embracing each other as the audience got to their feet.
Rihanna is a big fan of the pop princess.
'I want to spank Britney Spears,' Rihanna, 23, told New York's Z100 radio.
And Britney, 29, is pretty keen on Ri-Ri, too.�
'You're such a tease! I like it, like it...'
WATCH VIDEO Rihanna and Britney Spears perform S&M remix at the Billboard Music Awards...