TORONTO (Reuters) - Actor and producer Matt Damon says scheduling prevented him from starring in "Manchester by the Sea," a film about a man consumed by grief over the death of his brother and who is made legal guardian of a teenage nephew.


Casey Affleck, brother of actor Ben Affleck, was chosen instead to star in the film, which Damon supervised from its inception and produced.


"I wouldn't have let it go to anyone but Casey," Damon told Reuters at the film's premiere at the Toronto International Film Festival on Tuesday.


"That was really the condition because I was ready to do it. We were actually in pre-production but our time got so squeezed that we said 'Okay, let's punt.'"


For the production, which has been receiving rave reviews, Damon passed the directing baton to writer Kenneth Lonergan.


"I commissioned him to write it five years ago and I was supposed to direct it," Damon said. "And then I read the first draft and I was just bawling my eyes out and thunderstruck and I just called him immediately and went 'Kenny, nobody else can direct this. This is a Kenny Lonergan movie. You have to direct it.'"

Damon said he, Affleck and Lonergan had all worked together in the past, which made the process "comfortable."

However, playing a man suffering from perpetual grief didn't come as comfortably for Affleck.

"Every job has its own different challenges," Affleck explained. "In this case, that character has gone through a lot of hard stuff."

Actress Michelle Williams plays Affleck's wife in the film and the cast rounds out with Lucas Hedges as the nephew and Kyle Chandler as Affleck's brother.

The U.S. release of "Manchester by the Sea" is slated for Nov. 18.

(Reporting by Reuters TV; Editing by Paul Simao)