Barbie as the Princess and the Pauper (2004)
Barbie as the Princess and the Pauper is a 2004 direct-to-video computer animated Barbie film, and the first musical in the Barbie film series. It is directed by William Lau and stars the voice of Kelly Sheridan, who has been voicing Barbie in all the CGI films to date, as both Anneliese and Erika. The story is loosely inspired by the Mark Twain novel The Prince and the Pauper, but it is unrelated to the 1939 film The Princess and the Pauper. It is the first movie not to be told by Barbie but instead narrated by her.
More at Wikipedia.