Rihanna has no problem baring her bikini body for her more than 24 million Twitter followers on a near-daily basis, but this time, the singer is letting down her guard emotionally as well.

The "We Found Love" singer, 24, sat down with Oprah Winfrey for an episode of Winfrey's "Oprah's Next Chapter" recently and candidly opened up about her controversial relationship with her ex, Chris Brown.

PHOTOS: RIHANNA'S SEXIEST MOMENTS

"It was embarrassing. It was humiliating. I lost my best friend," she said. She told the talk-show host of how she reacted after the pair split up. "I was resentful. I held a grudge. I was dark."
Rihanna and Brown, 23, had a very public falling out in 2009 after Brown physically assaulted her on the eve of the Grammys, leaving her black and blue.

Rihanna posing with Oprah Winfrey.

The pair are reportedly now reconciled, however, after they released two collaborations together earlier this year. It is also rumored that they have been hooking up "on and off" since their public breakup.

Winfrey admits that she was surprised by how down-to-earth Rihanna turned out to be, especially in light of such tabloid reports.

Rihanna and Chris Brown at at 2009 Grammy even in Beverly Hills.

"I went there with my own ideas of who she was by watching the videos and listening to her music," Winfrey says in a promo for the episode. "I thought she was going to be a kind of a badass, kind of a hard-edged rocker, pop woman.

"Nothing could have been farther from the truth."

"She pushes the edge a lot," Winfrey notes, "and there's a reason for that."

Rihanna shows off her bikini body via her social network page.

Despite selling millions of records, garnering a loyal following in the Rihanna Navy, and being hailed as the most social celebrity in the world by Forbes magazine, the singer admits that her fame has come at a price.

"I am super duper terrified of the pedestal that comes with fame," she said.

"It's amazing how lonely you can feel."

The episode is set to air Aug. 19 on OWN.

Rihanna shows off her bikini body via her social network page.