Who knew prison could be this much fun? Okay, not really FUN but Sing Sing begins with a light mood. Men in prison in a repertory theater company. Workshopping ideas together and coming up with an amalgam of a show to be written by their leader Brent (Paul Raci) who comes from outside the walls.

It’s prison but it appears more orderly and civilized than prison is often depicted in films. The men stay in units that look more like dorm rooms than cells. They chat amiably at meals and in the yard—with a few exceptions.

What makes Sing Sing special is these prisoners in the film are, for the most part, formerly incarcerated men. They bring a special level of reality and humanity in their portrayals of prison inmates. Yes, they have been convicted of serious crimes but they are real, generally likable, people.

Divine G (Colman Domingo) is the alpha of the rep company. He’s also working to get his conviction overturned. G is cool and calm in his clemency hearing. But the pressure of being behind bars slowly builds. Domingo, who was an Oscar nominee for his portrayal of civil rights activist Bayard Rustin, is a compelling presence onscreen.

Also meriting special mention is Clarence Maclin, a former inmate, whose work on Hamlet’s “To Be Or Not To Be” soliloquy during the film goes from ludicrous to powerful. This is not the last time you’ll see him onscreen.

While the mood of Sing Sing is not as intense as that of some prison movies, there are reminders that the men are isolated from society. The frequent shots of men looking out at the Hudson River and of the trains traveling right next to the prison make that point clear. (The lyrics to Johnny Cash’s Folsom Prison Blues came to my mind each time the train rolls by.)

Sing Sing is likely to be in conversations in a few months when awards season kicks in. Not just for Domingo and Maclin but for the film’s director Greg Kwedar who co-wrote the script with Clint Bentley. It is one of the best movies to be released so far this year. Rated R for language.