Taken from the E3 preview and predictions thread.
So, I was listening to the PS Nation Podcast (Episode 427: PrE3) and about 1:02:00 in, Stewart Gilray (of Just Add Water) heavily implied that Mark Cerny's team (the team that built Knack?) might be the team finishing development on the The Last Guardian.
http://www.psnation.com/2015/06/08/episode-427-pre3/ Edit- For some reason, the timestamp was different on iTunes. In the link, it actually occurs around 49 minutes (almost exactly). I don't get why there was a 10 or so minute difference.
The Cerny rumor is... interesting. Funny I've heard it for the third time!