Katy Perry Apology to Chief Keef Chills Feud

Katy Perry found herself in an unlikely Twitter feud with rapper Chief Keef earlier this week.

On Tuesday, the 28-year-old pop star tweeted her disapproval of Keef's song "I Hate Being Sober," a NSFW track also featuring 50 Cent and Wiz Khalifa. Instead of brushing off the criticism, Keef (real name: Keith Cozart) blew up, spewing hateful epithets at Perry on the social networking site.

What started it all was when Perry tweeted, simply, "Just heard a new song on the radio called 'I hate being sober' I now have serious doubt for the world"