Evidence keeps mounting that Rihanna and Chris Brown are back together, despite the fact that he insists they're just the "best of friends." Just last night, Rihanna tweeted a picture of a shirtless Chris Brown laying in bed, boxers on full display, TMZ reports. And they spent Thanksgiving together, photographed partying and then leaving a Berlin nightclub together, E! reports. En route to Germany, Rihanna tweeted, "All alone in my big ole jet!!! See u soon lover." And of course, they recently collaborated on yet another song pointedly titled, "Nobodies Business."