NEW YORK — America Ferrera has signed on to star in “An Invisible Sign of My Own,” a coming-of-age drama that will also mark Marilyn Agrelo’s first directorial effort since her breakout documentary “Mad Hot Ballroom.”

The movie, expected to begin shooting shortly, is based on Aimee Bender’s quirky novel about a 20-year-old loner named Mona Gray (Ferrera) who as a child turned to math for salvation after her father became ill. As an adult, Gray now teaches the subject and must help her students through their own crises. “Wedding Planner” scribes Michael Ellis and Pamela Falk penned the adaptation.

Endeavor put together the project, which will be produced by Jana Edelbaum’s iDealPartners Film Fund, the New York entity that’s also behind the Uma Thurman comedy “Motherhood” and Lionsgate’s Russell Crowe crime-saga “Tenderness.”

Ferrera will have a relatively short window in which to shoot the movie; the “Ugly Betty” star is on an aggressive production schedule for her ABC hit, with ABC Studios still in production on the show until early May and then going back into production in June as the show shoots ahead of a potential SAG strike. Ferrera is expected to shoot “Sign” between her “Betty” shoots.

The actress has been in demand since her ABC telenovela adaptation took off two years ago and has continued to manage a robust career in film, following up her role in Warners’ “The Sisterhood of the Traveling Pants” with a turn in this summer’s sequel. She also currently stars in The Weinstein Co./Fox Searchlight’s “Under the Same Moon.”

Agrelo’s “Ballroom,” about New York elementary school students who take up ballroom dancing, was an indie crossover in 2005, with the documentary earning $8 million. The director has not committed to any other directorial projects since, though she has optioned several books from comic novelist Valerie Block as a producer.