Some people are unhappy that Rihanna and Chris Brown are all buddy-buddy again. Katy Perry, RiRi's BFF, seems to be one of them.

According to a source, there has been some tension between the two since Rihanna reunited with Breezy and Katy has been opting to spend time with Robert Pattinson and Kristen Stewart instead.

According to the source, Katy wants no part in what she considers to be a huge mistake.

[via NY Daily News]