Quinto will play the former boyfriend of Franco's Michael Glatze, while Roberts will portray his girlfriend in the true-story drama.
Zachary Quinto and Emma Roberts are set to share screen with James Franco in "Michael", a movie about an anti-gay pastor who was once gay himself. Another new addition to the cast ensemble is Chris Zylka ("The Leftovers").
Franco will play the main character Michael Glatze. Quinto portrays Glatze's former boyfriend, while Roberts will reunite with her "Palo Alto (2014)" co-star as his on-screen girlfriend. Zylka lands a role of another past love interest to the former gay advocate.
The script is based on "My Ex-Gay Friend", a New York Times Magazine article by Benoit Denizet-Lewis. Justin Kelly serves as a director, while Gus van Sant who previously directed Franco as the love interest to Sean Penn's Harvey Milk in 2008's "Milk" is the executive producer.
"This isn't just a story about an 'ex-gay,' " Kelly said. "It's actually a very relatable story about the power of belief and the desire to belong." Denizet-Lewis added, "I'm excited that everyone involved in this project is intent on telling a story that captures the full breadth of Michael's unusual life, from the inspiring gay leader I knew when I was young to the Christian pastor he is today."