The Little Unicorn (2001)

Polly Regan (Brittney Bomann) has a good life on the farm with her grandfather (David Warner, Time Bandits). Unfortunately, one day Polly learns that her favorite mare is suffering with a difficult pregnancy and soon dies giving birth. Heartbroken, Polly finally comes around when she sees the new foal, who incredibly is born a real live unicorn, and soon earns the love of Polly and her grandfather.