Screenwriter Aaron Sorkin on Friday paid tribute to Jessica Chastain and Idris Elba for making his directorial debut, Molly's Game, easier to shoot, despite minimal rehearsal time and scheduling.

"I was super smart to make that decision. I really can't give myself enough credit," Sorkin said with a wry smile when discussing his movie at the Toronto Film Festival as part of a master class he gave at the Glenn Gould Theater.

In his directorial debut, Sorkin, whose screenwriting credits include A Few Good Men, Moneyball and The Social Network, chronicles Molly Bloom, a former competitive skier who ran high-stakes, star-filled poker games in L.A. and New York that eventually placed her at the center of an FBI investigation.

He said Chastain and Elba had six key, play-like scenes in Molly's Game where they appear together in a criminal lawyer's office. "Those are the kinds of scenes that you need rehearsal for, because you need to have ownership. ... There was no rehearsal time. At all," Sorkin recalled.

Instead, around six weeks before shooting, Sorkin, via Skype and email, began a "virtual rehearsal" with the actors. "But none of that would have mattered at all if Jessica and Idris did not show up every day completely prepared, not just having memorized their lines, but owning it," Sorkin said.

The half-dozen office scenes between Chastain and Elba were shot one after the other, one scene per day. Sorkin said Chastain and Elba took any moment they weren't on set to prepare for the next day's scene.

"They already owned today's scene, so they'd work on tomorrow's scene," he remembered. Following the world premiere of Molly's Game in Toronto, the movie will hit theaters on Nov. 22.

The Toronto Film Festival runs through Sept. 17.