Katy Perry has apologised to rapper Chief Keef after she insisted his latest single Hate Bein' Sober made her have "serious doubt for the world".

The I Kissed A Girl hitmaker took to her Twitter.com page earlier this week (22May13) to express her disgust at the track, which celebrates drinking and taking drugs, writing, "Just heard a new song on the radio called I Hate Being Sober... I now have serious doubt for the world."

Keef didn't take kindly to Perry's comments and tweeted in response, "Dat (sic) b**ch Katy Perry... I'll smack the s**t out her."

However, the pop star appeared eager to put an end to the feud when she reached out to Chief Keef on Thursday (23May13) to make amends.

She writes, "Mr. Keef! I'm sorry if I offended you. I heard a lot of people guesting on the song & didn't even know it was you in particular. Actually... I'm a fan of your Don't Like video tbh (to be honest). I was really just having a general opinion on our generation's desire to be constantly intoxicated. Believe me, I'm a lover not a hater."