Kristen Bell treated the audience at Disney's D23 Expo to a live performance of hit songs from her hit film "Frozen." The actress and singer channeled her beloved character, Princess Anna, and even performed an unreleased track from the film, WENN reported.

The expo, dedicated to all things Disney, took place over the weekend at the Anaheim Convention Center in California. The last day of the D23 expo featured the "Frozen Fandemonium" event, an hour-long finale celebrating the film's musical score, according to Inside the Magic. The songwriting husband and wife duo Kristen Anderson Lopez and Bobby Lopez were on-hand to discuss their compositions that have gained such a big cult following.

Lopez explained that the couple had written a song called "The Spare," which was intended for the character Princess Anna, the feisty younger sister of the Ice Queen Elsa. The lyrics were meant to convey Anna's struggle with growing up in her big sister's shadow, but it was cut from the soundtrack early on. Anderson Lopez asked Bell if she would mind singing the first two verses of the unreleased track. She obliged and took center stage in a cobalt blue lace dress.

"Maybe I can't be the perfect one and maybe I err on the side of fun," Bell sang animatedly in the voice fans have come to associate with the endearing Princess Anna.

After the short performance, Anderson Lopez said that the song was cut because the lyrics didn't dig deep enough into who Anna is as a character.

"But it did really help us find our Anna," Anderson Lopez said. "And working with Kristen really helped us find our Anna."

Watch Bell perform the unreleased song "The Spare" at the D23 Expo below.