Katy Perry Down on Rihanna for Dating Chris Brown: Report Larry Busacca/Getty Images Katy Perry and Rihanna were once BFFs, but now, a man reportedly has come between them: Chris Brown. Us Weekly reported that because of Rihanna's rekindled romance with Chris, their friendship isn't what it used to be. "They aren't tight anymore because Katy doesn't approve of Rihanna dating Chris," an insider told the magazine. At the Grammy Awards last Sunday, Perry, 28, and boyfriend John Mayer, 35, were sitting in the front row, while Rihanna and Brown were sitting in another part of the audience. At past Grammys, the two girls had sat right next to one another. A representative for Perry did not immediately respond to ABCNews.com's request for comment. It was also recently reported that Rihanna had fallen out with Perry because she didn't approve of Perry dating known womanizer Mayer. When asked about this by Rolling Stone magazine, Rihanna dismissed the report, and laughed, "Katy Perry can date anyone she wants. Besides, who the f*** am I to say anything? I could never given relationship advice to anybody! One of the most talked about moments of this year's Grammys was when Brown, 23, and Rihanna, 24, were spotted smiling and cuddling. The two walked the red carpet separately but once inside the Staples Center, they got cozy, when Rihanna, decked out in a red dress, photographed leaning her head on Brown's shoulder with a huge smile. Brown showed up to a court appearance Feb. 6 in Los Angeles on issues related to his probation with Rihanna by his side. RELATED: Chris Brown Shows Up to Court With Rihanna In a recent interview with Rolling Stone, Rihanna said public opinion doesn't matter. I wasn't going to let anybody's opinion get in the way of that. Even if it's a mistake, it's my mistake," Rihanna told the magazine, out Friday. "When you add up the pieces from the outside, it's not the cutest puzzle in the world," she says. But it's different now. SEE MORE: Rihanna on Chris Brown: "We Know Exactly What We Have Now"