Justin Bieber's appearance on 'Late Night With David Letterman' ended up including a bit of an art history pop quiz -- and one that the Canadian singing sensation failed comically.

It all started with The Biebs showing Letterman how he had the word "believe" tattooed onto his arm to celebrate his new album of that name. This disappointed the curmudgeonly talk show host, who made it clear he doesn't like tattoos. In fact, Letterman tried to pull the ink of off Bieber's skin, resulting in the 18-year-old squealing out in pain!

Eventually that assault ended, and a calmer Letterman advised Bieber not get any more tattoos, lest he look like Michelangelo's famously busy "Sistine Chapel" interior. Watch the funny way Bieber responded to that recomendation.

"I'm not going for the Sixteenth Chapel look," Bieber shot back, mangling the name of the legendary work of art much to the crowd's amusement.

"Canadian high school," Letterman quipped.

Were going to have to give Bieber a pass for his gaffe. We'd be pretty mentally disheveled too if David Letterman just tried to rip off part of our skin.