Justin Bieber & Ke$ha Rock 99.5FM Jingle Ball

Bringing their powerful pop prowess to the stage, Justin Bieber and Ke$ha both gave exciting performances at the 99.5FM Jingle Ball in Washington DC last night (December 11).

Donning a glittery getup, the “TiK ToK” songstress threw a white Gibson Explorer guitar over her shoulder and played through her hit-laden set.

From there, Justin kicked things off with plenty of swagger, even lifting up his shirt to show off his six-pack for the lucky ladies in the first few rows.

The day before, Mr. Bieber was apparently having a rough time as he ended up throwing a plastic water bottle at a gaggle of shutterbugs while out and about in DC.

Enjoy the pictures of Justin Bieber and Ke$ha at the Hot 99.5's Jingle Ball 2012 (December 11).