Frozen: Fever Announced

The filmmakers who brought us the animated hit musical "Frozen" in November 2013 have created a seven-minute short centered around Princess Anna, Princess Elsa, Kristoff and the snowman Olaf. Frozen Fever will show in theaters before Disney's live-action Cinderella, out March 13.

The first revisiting of the now-beloved characters features some surprising changes, including older sister Elsa's attitude. Elsa, weighed down by her royal duties in Frozen, has lightened up so much that she's throwing Anna a birthday party.

The short features a new song from the husband-and-wife team of Robert Lopez and Kristen Anderson-Lopez, who won an Oscar for Let it Go. Be warned: The next "Let It Go" is on it's way. 

The Frozen landscape is also changed, as the kingdom embraces warm weather and Anna's summer solstice birthday. The directors promise other surprises as well. But the sister's rock-solid support for each other doesn't change from Frozen, which took in more than $400 million at the box office.