Yes, GarageBand is the app in the commercial. Why would Apple feature someone else's piano? :-) But it is nice that they said "App from App Store" instead of being more specific. That allowed the rest of us piano app developers to benefit.

p.s. I hope I'm not the only one around here who thinks of Tom Hanks when I hear that tune. I suppose all the kids downloading my app don't think of "big" when they see the TV ad.