There are already four new songs in the works for the sequel, and it sounds like one of them just might be the new "Let It Go." "We have a new song that I think is an evolution," co-director Jennifer Lee told Variety. "It's its own song . . . Bobby [Lopez] and Kristen [Anderson-Lopez] just delivered it three weeks ago. We've been working with them for two years and this song just came in and I love it."