Crotchety David Letterman gave Justin Bieber a stern lecture on his show last night that left the pop sensation a little speechless. What had Dave so riled?

It was a little odd that the pop sensation popped up on Letterman’s CBS show at all, on the same night the second part of Justin’s “Round the World” special aired on NBC.

Usually the networks try to lock up all the residual publicity when they air a big production. Justin rightly should have appeared on Jay Leno’s “Tonight Show” on the same network.

So cudos for Dave for landing the Biebs. Although Justin may not have felt that way. Dave put him in the hot seat over his tattoos.

“Is that a new tattoo,” said the curmudgeonly Dave, gesturing at Bieber’s right arm.

“This is a new tattoo,” Justin replied.

“Oh god, how many do you have?” said Dave.

“I have ju..just a couple,” Justin stammered as if he were talking to his grandpa.

“Well, tell me that’s the last one,” Dave said.

“It might be,” said Justin.

For the record Justin had the word “Believe” tattooed on the inside of his right arm to celebrate the release of his new album. Dave got feisty after that. Check out the video below.