LOS ANGELES, CA - FEBRUARY 12: Singers Rihanna and Katy Perry in the audience at the 54th Annual GRAMMY Awards held at Staples Center on February 12, 2012 in Los Angeles, California. (Photo by Larry Busacca/Getty Images For The Recording Academy)

Singers Katy Perry and Rihanna were once best buds but they seem to be spending more time apart lately, and Chris Brown may be to blame.

According to a source for New York Daily News, Rihanna’s decision to reignite her relationship with Chris Brown has caused “tension” between the two musicians.

Like many other people around Rihanna, the source is afraid that “Rihanna is making a huge mistake and [Perry] doesn’t want to be a part of it.”

Perry didn’t even attend Rihanna’s Halloween bash in Hollywood and has been spending a lot more time with her friends Robert Pattinson and Kristen Stewart. The two pop stars are “barely talking.”

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