Britney Spears voiced her support for the Once Upon a One More Time musical to celebrate its opening night on Broadway on Thursday.

The pop singer shared words of encouragement on Thursday night for the cast of the musical, which is "powered by" her greatest hits, including Oops!... I Did It Again, Lucky, Toxic, and Stronger.

"Good luck to the hard working cast and crew of Once Upon a One More Time on opening night tonight!!! I've seen the show and it is so funny, smart and brilliant!!!" the 41-year-old wrote on Instagram.

The show is a jukebox musical comedy set in a fantasy storybook realm. The plot follows several classic fairy-tale characters, including Cinderella, the Little Mermaid and Snow White, as they are transformed by a feminist awakening after starting a book club.

The musical, which was produced by Tony winners James L. Nederlander and Hunter Arnold, opened at the Marquis Theatre on Thursday night following previews, which began on 13 May. It has received mixed reviews.

Nederlander and Arnold previously confirmed that the Grammy winner fully authorised and licensed her music for the stage production in 2022 following the end of her conservatorship in November 2021.

Arnold told The Hollywood Reporter, "Everybody involved really believed for this thing to work spiritually, it has to be a homage to the iconography of her career, and it has to be a direct benefit to her."