Entertainment

WATCH: Letterman lectures Bieber, then grabs his new tattoo

Justin Bieber received the “grandson” treatment on “Late Show with David Letterman” Thursday, enduring a lecture about tattoos, voting and education from the curmudgeonly host.

Biebs visited the show to promote his latest album, “Believe,” which was released in the US Tuesday.

Justin carried the album title on the inside of his left arm, the word tattooed in big block letters. Letterman, 65, was not impressed.

“Explain this to me, is that a new tattoo?” the host asked.

“This is a new tattoo,” Bieber responded.

“Oh God, how many do you have?”

“I have a … just a couple.”

“Well, tell me that’s the last one.”

“Might be.”

“No, it is,” Letterman said, perturbed. “Honestly, how does that help how you look to have a tattoo?”

“How does it not? It doesn’t not help the way I look.”

Bieber started explaining the reasons behind his ink, when an agitated Letterman grabbed for the singer’s arm.

“Hey! Hey! Hey! Hey! Hey! This is brand new!” Bieber said, smiling as Letterman pulled away. “Grandpas.”

During the segment, Letterman also admonished Justin over the importance of voting (even though, as a Canadian resident, Bieber can’t vote in US elections), as well as the significance of a college education.

“I think he needs guidance from (me),” the host said.

Letterman later apologized for his behavior, saying he was told he was being “snappish” during his interview with Bieber.

Biebs brushed it off, saying Letterman was “fine.”

But the host’s momentum was noticeably faded as he introduced Bieber’s performance of “Boyfriend” to close the show.

The Bieber-Letterman exchange struck a chord about youth and ego and age. Letterman has been hosting a late-night talk show since 1982 – 12 years before Bieber was born. Among the current late-night TV hosts, stalwarts Letterman and Jay Leno are counterbalanced by Conan O’Brien’s viral moments, Jimmy Kimmel’s YouTube gold, and Jimmy Fallon’s drinking games.

Bieber also made an appearance on Fallon’s show Thursday, with the pop superstar and host facing off in a series of competitions, “big brother” versus “little brother” to settle their dueling album releases.

The duo engaged in video game warfare, laser tag, checkers, breath-holding (“85 seconds — yes!” Fallon proclaims, celebrating his win), pushups, Marco Polo, and an epic juice break.

But after all the events are complete, the competitors are still tied.

“Sudden death dance-off,” they decide, with Bieber slinking his way to victory over Fallon’s middle school moves.

Where Fallon adapted to his guest’s talents, Letterman appeared critical and un-hip, the “grandpa” at the dinner table spouting unheeded advice over Thanksgiving dinner, the 60-something who doesn’t understand the most popular teen in the world.