Posted on Tue Dec 4, 2012 10:55 AM PDT
Getty Images for Clear Channel
Justin Bieber knows how to get the crowd going wild!
The "Baby" singer hit the stage at KIIS-FM's Jingle Ball show at the Nokia Theatre in L.A. wearing a sexy black shirt. We couldn't help but notice those bulging muscles. Pump it up, Biebs.
As for Ke$ha, the 25-year-old "Die Young" singer strutted her stuff in a gold leotard and even did a cartwheel. Whoa ... that's a whole lot to look at!
See more pics from the show in our gallery below.
SEE THE GALLERY Ke$ha And Bieber Rock The Jingle Ball
Justin Bieber Cruises Around Town With Ladylove Selena Gomez - Dec 03, 2012
Justin Bieber Shows Off Ripped Body While Pumping Iron - Nov 30, 2012
Justin Bieber Dishes To Oprah About His Relationship With Selena Gomez - Nov 26, 2012
Justin Bieber Gets Into The Holiday Spirit With Black Friday Commercial - Nov 21, 2012
Justin Bieber And Selena Gomez Enjoy Date Night At Benihana - Nov 20, 2012