Hayden Panettiere is joining yet another large ensemble cast for her latest film project.

The "Heroes" actress and four other actors -- Willem Dafoe ("Spider-Man"), Ioan Gruffudd ("Fantastic Four"), Shannon Lucio ("The O.C.") and George Newbern ("Father of the Bride") -- have signed on for Senator Entertainment's "Fireflies in the Garden."

According to The Hollywood Reporter, the story is based on Dennis Lee's screenplay that's based loosely on his life and examines love and commitment in a family tested by an unexpected tragedy. There's no indication of who will play what role.

"We are quite fortunate to have secured an ensemble with such talent and global boxoffice track record," says Senator's Marco Weber, who is producing with Vanessa Coifman and Sukee Chew. "Their desire to be involved with this film clearly shows the quality of the script."

The fivesome joins the already cast Julia Roberts, Carrie Anne Moss, Ryan Reynolds and Emily Watson.

Lee will also make his directorial debut on the project. Production is scheduled to begin April 3 in Austin.

Panettiere is best known as the indestructible teenager on NBC's "Heroes." Her film credits include "The Affair of the Necklace," "Raising Helen," "Racing Stripes," "Ice Princess" and the straight-to-DVD release of "Bring It On: All or Nothing."