I think I just found the answer perhaps here https://youtu.be/HOh5zUOww0E using a tilt shift lens!
Thank you Robert for the very comprehensive response...that is exactly the kind of information I too was seeking!
Thank you. I was wondering the same thing. Good to know!
Thanks heaps. Time I got some more powerful lights I think!
Oh gee, now I'm really confused because I've watched Film Riot and they said it's the fill light or bounce that makes the high key look. https://youtu.be/2Y6bB86HmdA?t=3m4s
Thank you Craig. This would pretty much imply that I would shoot with a flat profile on my GH4 and then the high key look happens in post whereas the tutorial I watched https://youtu.be/4DDIvWv27Y8 said the secret is to have a very dominant key light to reduce the shadows.