Justin Bieber has had quite the whirlwind week taking Bieber Fever all over the country. He did make time though to get some new ink in celebration of his album release. Last night on the Late Show with David Letterman Bieber filled Letterman in on his reasoning.

“This is a new tattoo. . . I have just a couple,” Bieber said after Letterman asked him about a tattoo on his left forearm.

“Well, tell me it’s the last one,” Letterman pleaded before adding, “How does that help how you look, to have a tattoo?

“It might be. How does it help?” Bieber asked. “It doesn’t not help the way I look. It just expresses me. Yesterday my album came out it was an important day for me so I got Believe . . . ” Bieber said before Letterman cut him off and tried rubbing the tattoo off.

Bieber was a good sport though, referring to Letterman as “grandpa.”

good times hanging with my uncle dave (maybe grandpa now. lol) at the @late_show – gonna hit the stage. 1 HOUR until #BIEBERonNBC though — Justin Bieber (@justinbieber) June 20, 2012

sang for uncle…grandpa dave. — Justin Bieber (@justinbieber) June 20, 2012

“Do me a favor, don’t go nuts,” Letterman requested. “More and more you see the mural and the Sistine Chapel. It’s too much.”

Justin confirmed that while his mom isn’t too pleased, he won’t be going for “the 16th chapel look” any time soon.

-Annie Reuter CBS Local