Walt Disney Animation has announced a new short based on the characters from Frozen debuting in the spring of 2015. Frozen Fever will feature a new song by Robert Lopez and Kristen Anderson-Lopez who won an Oscar for Let It Go.
Directed by Jennifer Lee and Chris Buck the new short finds Queen Elsa (Idina Menzel) and Kristoff (Jonathan Groff) preparing a birthday celebration for Princess Anna (Kristen Bell), though Elsa's icy powers complicate matters a bit.
Disney has not said which movie it will attach the short to, but speculation is that it may play with Kenneth Branagh's live-action Cinderella which is due out March 13th, 2015. Disney also has a movie coming out on May 1st, 2015 but I think running it in front of Avengers: Age of Ultron would be a long shot but an interesting marketing move.