The flame-haired R& B singer recently took a shot at Perry's music in an interview with BBC's Radio 1, reports the New York Daily News.
While on the air promoting her new album, "Loud," Rihanna lashed out at Perry's radio-friendly hits.
"I didn't want the generic pop record that Ke&sha or Lady Gaga or Katy Perry would do," she said. "Every song was tailored to me."
That swipe is somewhat shocking given that the "Rude Boy" singer recently hosted Perry's bachelorette party in Las Vegas last month. The two ladies partied at the Hard Rock Hotel, caught a Cirque Du Soleil show, and even hit up a strip club.
There's been no response from Perry, who is currently in Germany peforming on "Wetten, dass...?," a language game and entertainment TV show whose name means "Wanna Bet?"
"I'm starving, what should I have for lunch...Beer? Time to bust out my wench dress. God knows I've got the rack for it. #oktoberfest," the "Teenage Dream" singer wrote on Twitter after she wore a dirndl, a traditional dress associated with southern Germany, on the show.
Rihanna is set to appear on "Saturday Night Live" on Halloween eve, just five weeks after Perry did the same.