Sorry if this has been mentioned already, but take a look at the timetable for the stream.
http://blog.us.playstation.com/2015/12/03/playstation-experience-2015-everything-you-need-to-know/
At 2PM, There's 'Playstation VR and The Future of Play'. Participants include 'Special Guests'. Since this part of the stream is about the upcoming VR and the 'Future', it would make sense to showcase GT Sport then.
I might be hyping too much, but nowhere else on the timetable does it say 'special guests'. It could be Polyphony Digital. Better yet, they will show us a VR demo of the game.