And the Bajan beauty was stunned when the Baby singer lifted his top to show off his impressive abs - and she admits she found his cheeky flash "sexy".
In a post on her Twitter.com blog, Rihanna writes, "Justin Bieber just flashed me his abs in the middle of a restaurant! Wow! He actually had a lil 6 pack! Sexy, lol (laugh out loud)!"
And Bieber was clearly happy with the compliment - he responded by posting a photo of the two stars together at the restaurant, adding: "It's always love."