Katy Perry is not happy with her BFF Rihanna. Apparently Rihanna is working with Katy Perry's ex boyfriend, John Mayer. According to an anonymous source, Rihanna wants Mayer to lay down vocals for a new track she's working on.

Even though Perry is now dating DJ Diplo, the pop songstress is reportedly still upset that her friend is violating 'girl code.'

But sometimes business crosses personal boundaries even though people try to keep them separate, right? Tell me what you think below.

[The Hollywood Gossip]