Justin Bieber is ready to go all gangsta on the drummer of the Black Keys.
Well, theoretically ... as long as all those bodyguards are still around.
Bieber apparently didn't like the Black Keys drummer Patrick Carney saying after Sunday night's Grammys that Bieber doesn't deserve a Grammy because those are basically for good music, but should instead be happy with all the money he makes.
"He's rich, right?" ... Grammys are for music, not for money ... and he's making a lot of money," he said.
It's a pretty good point, actually. Then again, he's a drummer ...
So Bieber took to Twitter a day later, to retort, saying the drummer "should be slapped around."
Bieber added "haha" at the end of his statement -- which he posted on Twitter -- like he was joking.
Just for the record, TMZ pointed out that the Black Keys currently own a 7-0 lead on Bieber when it comes to Grammys.