Disney says the release is to surprise "families with some fun and joy during this challenging period."
Bob Chapek, Chief Executive Officer, The Walt Disney Company says:
Frozen 2 has captivated audiences around the world through its powerful themes of perseverance and the importance of family, messages that are incredibly relevant during this time, and we are pleased to be able to share this heartwarming story early with our Disney+ subscribers to enjoy at home on any device.
According to Disney, Frozen 2 "will be available on Disney+ in Canada, the Netherlands, Australia and New Zealand on Tuesday, March 17. In the U.S., the film will initially be available in high definition, with Ultra HD video playback available to all subscribers on Tuesday, March 17."
You can learn more here.