Rihanna is enjoying her Hawaiian vacation, tweeting a photo of herself wearing a tiny, white bikini while on a cross trainer machine, with the message: "Haha, come tap this @Khloekardashian!!!" Khloe replied, "Don't tempt me doll! LOL!"
The 23-year-old treated fans to several more bikini pics, and when someone asked how the singer keeps such an incredible figure, Rihanna replied, "Angles/Lighting/Photoshop :)"
The "We Found Love" songstress recently added her 12-millionth Twitter follower.