Earlier today, Square Enix held a private press conference at E3 2013 known as "Square Enix: The Future". Following the official announcement of Kingdom Hearts III yesterday, here, various small details about Kingdom Hearts III were revealed. Most importantly, it was revealed that Kingdom Hearts III will be released on both the PlayStation 4 and the Xbox One. For the first time, Kingdom Hearts is going multi-platform with KH3!
Thanks to @RPGSite, a photo of this announcement is below.