It was for a SHINee World 音乐会 for Key's solo song 'My first Kiss". He dressed up as a girl because it was original suppose to be Krystal (From Fx) but I think she couldn't make it to one of the concerts so they used Taemin :P and the 粉丝 loved it so much that just kept it that way ^ ^;; I hope that helped.. :O here is a video from one of the 音乐会 XD
