Sara Paxton has signed on to star as the lead in 20th Century Fox's comedy
Aquamarine, says the Hollywood Reporter.
The project, helmed by Elizabeth Allen, is based on an Alice Hoffman children's book, and centers on two 12-year-olds who discover a mermaid named Aquamarine (Paxton) in their beach club's swimming pool.
Teen pop-star JoJo and teen star Emma Roberts have already been cast as the two girls.