Oprah Winfrey isn't afraid to ask tough questions, as Rihanna quickly learned when the 58-year-old TV mogul interviewed her for Oprah's Next Chapter.
When asked about her former relationship with Chris Brown, who pleaded guilty to physically assaulting her in February 2009, Rihanna teared up. "It was embarrassing. It was humiliating. I lost my best friend," the 24-year-old pop star said.
Post-split, "I was resentful. I held a grudge," Rihanna admitted. "I was dark." Rihanna and Brown, 23, have since reconciled, both personally and professionally; a source told Us Weekly they hooked up "on-and-off" for nearly a year in 2011, and the two collaborated on two remixes in early 2012.
Winfrey admitted she was surprised by Rihanna's tender candor. "I thought she would have been kind of a bad-ass kind of a rocker hard-edge woman -- nothing could have been farther from the truth," she said. "She was thoughtful. She was very emotional. She was vulnerable."
"She pushes the edge -- she pushes the edge a lot, and there's a reason for that," Winfrey added.
Oprah's Next Chapter airs Sunday, August 19 at 9 p.m. EST on OWN.