William Moseley has booked a starring role in A Little Mermaid, and Diahann Carroll, William Forsythe and Gina Gershon have joined the supporting cast. Based on Hans Christian Anderson’s 1837 fairy tale, the live-action family film starring Poppy Drayton, Loreto Peralta and Shirley MacLaine.

A Little Mermaid centers on Elle (Peralta), a young orphan who discovers a beautiful and enchanting creature (Drayton) she believes to be the real “Little Mermaid.” Moseley will play Cam Harrison, Elle’s overprotective older brother who has come to the U.S. to live after the deaths of her parents. A newspaperman, he is sent to a small Mississippi town on an assignment to find out more about some mysterious healing waters and ends up learning more than he ever imagined about the power of love, belief and magic — both light and dark.

Chris Bouchard directs and Blake Harris scripted the pic, which is the first project for MVP Studios founded by Robert Molloy — the grandson of former New York Yankees owner George Steinbrenner — and producer Armando Gutierrez. The will be released next year.

Moseley is a regular on E!’s drama The Royals and co-starred as Peter in the Chronicle of Narnia films. He is repped by APA, Untitled Entertainment and attorney Lev Ginsburg. Gershon is with Abrams Artists Agency and Untitled, and Forsythe is with Abrams and the Arlick Group.