Jessie Mueller and Barrett Wilbert Weed Cast in Workshop of Sara Bareilles' Waitress

Waitress, a new musical with a score by singer-songwriter Sara Bareilles and a book by filmmaker Jessie Nelson, recently held a workshop in anticipation of its August 1, 2015, world premiere at American Repertory Theater. The production is directed by Diane Paulus, the artistic director of the Massachusetts-based theater.

Based on Adrienne Shelly's 2007 film of the same title, Waitress tells the story of a pregnant diner employee who longs to escape her abusive marriage and find her storybook ending. The film's principal cast included Keri Russell, Nathan Fillion, Cheryl Hines, Jeremy Sisto, Andy Griffith, and writer-director Shelly, who was murdered shortly before the movie hit cinemas.

No casting for the full production has been announced, though the workshop starred Tony Award winner Jessie Mueller (Beautiful — The Carole King Musical), alongside Christopher Fitzgerald (Finian's Rainbow), Eric Anderson (The Last Ship), Amber Iman (Soul Doctor), Barrett Wilbert Weed (Heathers), Keala Settle (Les Misérables), and Andy Karl (Rocky), among others. Mueller has long been rumored to take on the leading role in the show.

Bareilles is a five-time Grammy nominee whose songs include "Love Song" and "Brave." Nelson is the screenwriter behind the films Stepmom and I Am Sam, among others. Paulus is the Tony-winning director of Broadway's Pippin and the artistic director of the American Repertory Theater.

Waitress is being developed by producers Fran and Barry Weissler.