(Photo : instagram/ Justin Bieber)

Justin Bieber got down and dirty during the Q102 Jingle Ball at Wells Fargo Center in Philadelphia on Dec. 5. The 18 year-old flashed his ripped physique to a crowd full of streaming girls. Bieber admits he has been working out to get buff and "sexy for the ladies."

"I've been working out in the gym, getting bigger, trying to get sexy for the ladies," Justin Bieber said, according to Examiner.

Bieber, who is only 5'7" and fairly thin, has been showing some improvement in his body stature.

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"While Justin may not objectively be 'ripped,'" Examiner reports. "It's a dramatic transformation from the string bean he was during the past few years."

Bieber recently tweeted a picture of his newly developing six pack. And in 2010, Bieber showed off his abs to Rihanna, which she called "sexy," on Twitter.

(Photo : Instagram/ Justin Bieber)

"Justin Bieber just flashed me his abs in the middle of a restaurant! Wow! He actually had a 'lil 6-pack! Sexy, lol!" she wrote.

Check out more photos here!

Justin Bieber and Selena Gomez finally seem to be getting back to normal. The young couple have seen a fair share of drama the last few weeks. After sources reported they had officially split, fans lost hope for Jelena. However, photos reveal Justin Bieber and Selena Gomez driving in his Italian Ferrari 458. They appear back together and back to normal.

Bieber showed off his flashy wheels to Gomez as they strolled past Beverly Hills on Monday, Dec. 3. Rumors suggested that the night before, the happy couple were spotted at the Wolfgang's Steakhouse, hand and hand, to have dinner.

When news of Justin Bieber and Selena Gomez break-up exploded, many fans expressed mixed reactions. While some Twitter fans lamented their sad break up, Justin Bieber fans girls also delighted that their favorite heart-throb was now on the market.

"JUSTIN BIEBER IS SINGLE. SCREW ALL OF YOU GUYS, I'm bout to get my mannnn!" one Twitter fan wrote.

"OMG Justin Bieber is single! He doesn't know I exist, I live on the opposite end of the planet, he could have any girl in the world..BUT YAY"

"JUSTIN BIEBER IS SINGLE!??!!? AKJLSDFHJGB;LAKBERHglvdjgk,l vbdfhsbotjdnlxjz fglsrgvae.zkh vDSBFRG"

"@JUSTINBIEBER YOU'RE SINGLE I'M SINGLE. OMG OMG OMG#MATCHMADEINHEAVEN"

"Best day ever... Justin Bieber is single and I got a car. (:"

"Justin Bieber and Selena Gomez broke up, therefore he's singleand i'm single, definetely getting together #IWisssshhhhh"