2AM's Jo Kwon recently revealed a photo of his bruised legs.

On December 27th, Jo Kwon uploaded the photo above tagged as, "It's all done. I'm happy to give a successful 'Joritney Kwonspears' performance. But I am black and blue all over after the performance. I have stiff neck and my back is sore."

Known for his dorkiness, Jo Kwon electrified the audience with a surprise parody performance of Britney Spears' "Till the World Ends" during 2AM's Christmas concert on December 24th and 25th.

Netizens commented, "You must have been in pain", "The leader really works hard" and "You are so great".