The 32-year-old actress will play a brand new character created for the film, reported Digital Spy.
"My Little Pony: The Movie" will also star Kristin Chenoweth and other main characters from the TV series, to be voiced by Tara Strong, Cathy Weseluck, Andrea Libman, Tabitha St Germain and Ashleigh Ball.
Jayson Theissen is directing the project due for November 3, 2017 release.