I have a video here:
As you can clearly see, "pianist" Marc-Andre Hamelin is trying to sneak in an orchestra to the Gershwin Piano Concerto in F, probably to hide his lack of technique. This image shows exactly where it is:

There is a large, black, wooden box-thing that Hamelin is sitting in front of. Now, I have no idea what that thing is or how it's used, but I'm pretty sure it's an orchestra.