Danny Devito on WhoSay
PS22 rehearsing 'Let it Grow'. I don't know if you've heard of PS22 chorus yet, but they are awesome and they sang this at the event. Also I hope we'll get video of Zac and Danny reading soon!
ETA: I can't embed it but Random House posted video of the kids singing at the event here, ty to mirandagirll for pointing it out to me :)