Justin Bieber "Pumped" to Grow Mustache

Credit: Neil Mockford/FilmMagic

He lost 80,000 Twitter fans when he cut his trademark bangs and now Justin Bieber, 17, is set to shake up his hair situation again.

"im not shaving for a month so you all can see my mustache," he wrote on his Twitter page Saturday. "i'm pumped."

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No word on what girlfriend Selena Gomez will think of the new facial hair, though it's clear the "Baby" singer, who's currently touring Europe, is thinking about his best gal.

"@selenagomez I miss you," Bieber tweeted Sunday.

Gomez wrote back, "@justinbieber I miss all of y'all."