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Wonderwall Editors

All it takes is two photos of Justin Bieber's lanky, 18-year-old chest and a Twitter trend is born.

This week, a pair of pics of the shirtless Biebs appeared on the social media site, and by Friday, the hashtag DAILYSHIRTLESSBIEBERPIC was trending.

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The king of the Beliebers posted the latest photo Friday afternoon, when he looked like he was still smarting from the pain of a new tattoo. "Its a crown if you couldn't tell," he explained in a caption below the close-up shot of his barely voting aged pecs.

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While Justin's obsessed fans couldn't be happier about the new ink -- and its spawn of a "daily shirtless Bieber pic" -- the singer better be ready for a tongue-lashing if he ever gets invited back on "Late Night With David Letterman."

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During his July appearance, shortly after he had inked the word "believe" on his arm, Letterman yanked the singer's hand and demanded that the latest tat better be Justin's last because "more and more ... like the Sistine Chapel, it's too much."

Bieber's now infamous response? "I'm not going for the Sixteenth Chapel."

Guess Letterman's chastising didn't stop him from going for the seventh tattoo.