We're getting a sneak preview of Oprah's upcoming interview with Rihanna as part of Oprah's Next Chapter. And in the video clip, you'll see the pop songstress open up about her failed relationship with Chris Brown, who assaulted Rihanna back in early 2009. On the incident, she notes that it was "embarrassing" and "humiliating." She then adds, "I lost my best friend." You can watch the preview above.