Kristen Bell (Anna), Josh Gad (Olaf), and Jonathan Groff (Kristoff) all got together in the real world to sing a little ditty about the making of Frozen. From here on out, all animated musical film actors should be forced to do a real life set, with the real life animators/professional dancers who created their characters.
It's good old fashioned musical fun. Plus it's nice to see Disney throwing the very talented Broadway star Jonathan Groff a bone, as his character wasn't given a song in the movie.
Sorry here's the full thing, with a weird frame.