First of all, Jino is not Baekhyun and he won’t be a part of EXO（ｉДｉ） Yeah, it sucks, but the 12 members have been revealed and you can find them here or here. Baekhyun’s birthday - May 6, 1992, Jino’s - April 17, 1992.
Second, ‘What is Love’ is not EXO’s debut song. It’s more like a teaser for D.O. and Baekhyun. SM Entertainment said it was a prologue single. Here’s the description “First Music Video ‘WHAT IS LOVE (Korean Ver.)’ presents singing ability of EXO members, BAEK HYUN & D.O.! More teasers will be released soon, so stay tuned!!!” More teasers will be revealed soon, this is not their official debut single/MV.
And we don’t know the date of their official debut either. SME hasn’t said anything about this yet.
Anyway, just clearing this up ‘cause we’ve been getting a lot of questions regarding these issues.
(Source: fy-exo)
