Sharon Osbourne

Brace yourself for a throw down, old-lady style, because Justin Bieber's grandmother isn't going to like this one bit: Heavy metal mama Sharon Osbourne has just become the latest celebrity to dump on the beleaguered singer.

Lady Gaga is getting another word in edgewise in the ongoing saga involving Kelly Osbourne and her mom Sharon Osbourne. After Sharon posted a response to Gaga's original open letter, the Mother Monster is back with another retort.

After Lady Gaga penned an open letter to Kelly Osbourne that essentially told her to stop being such a bitch (we're paraphrasing here), Sharon Osbourne jumped in to defend her daughter. As a result, insults are being hurled and fans on both sides are involved in heated slapfights. In other news: Timmy pulled Susan's hair during recess and now he has detention.