Prominent Italian thesps Toni Servillo (“The Great Beauty”) and Silvio Orlando, who plays Cardinal Voiello in “The Young Pope,” had never had a chance to share the screen before director Leonardo Di Costanzo cast them – respectively as a prison guard captain and an incarcerated Mafia boss – in his prison drama “The Inner Cage.”

This naturalistic film is shot in an ancient rural prison on the island of Sardinia with real ex convicts and former correctional officers also in the cast. The plot turns on growing tensions between the guards and inmates and the dynamics of finding a way to coexist when the facility is due to be shut down and thus partly evacuated, then left in an administrative limbo. This forces a skeleton staff to remain and guard a dozen prisoners who can’t be moved elsewhere yet. In this predicament they find a way to make their mutual captivity more bearable.

Following the film’s premiere in Venice, where “The Inner Cage” screened out-of-competition, Servillo and Orlando spoke to Variety about the challenges of their roles and the fun they had playing off each other. Excerpts.

Silvio, how was it acting with Toni with whom there is a sort of dueling dynamic?

Orlando: I don’t like to beat around the bush. Between actors there is [always] competition. Especially in film, where there is the battle for close-ups and so on. We are like chickens in the same cage. So on my part, initially, there was some anxiety in confronting Toni whose star in recent years has risen so much that he has an almost mystical aura. I also felt the responsibility of playing this character [a Mafia boss] who is very different from the happy-go-lucky types I often portray. I don’t think my physicality is very threatening, so I had to use glances and silences.

Servillo: The idea of giving us roles that went against the grain of the characters that we’d played before was a winner. Of course audiences could have expected me to play the criminal and Silvio to play the prison guard. But inverting the roles put us in an uncomfortable position that made it more challenging for us. Silvio and I come from a similar background in the Neapolitan theater world; we’ve always been curious about each other. So our common background shielded us from any [artistic] envy.

The other key aspect is the film’s screenplay where it’s the criminals who prompt the guards to take action. In particular it’s Silvio’s character who sparks the interior conflict of Gaetano, the character that I play. And puts him at the center of this strong push and pull between his sense of responsibility and his sense of compassion.

Regardless of competition between actors, there is competition between the characters you play. It’s sort of like a duel at times. Silvio, was it difficult to find the ferocity within yourself to play a Mafia boss?

Orlando: Acting for me is the art of memory. You have to find aspects of the character within yourself. This character is the farthest from me one could imagine, and I say this with all due respect for criminals.

But one thing I latched on to is that he’s a natural leader. And the interesting thing is that Toni’s character also becomes a leader. But in his case what’s interesting is that he becomes one by doing everything a prison guard shouldn’t do.

Did you guys do lots of rehearsals and reshoots, or did the performances just flow?

Servillo: There was a long preparation before we started shooting. In part that was so that we could get to know the non professional actors, some of whom are former inmates while others are former guards.

But it’s also part of Leonardo’s methodology to use the screenplay just as a basis, from which the actors can stray. So we talked about these characters and rehearsed the key scenes a lot. Like the moment when I sit down and eat with the inmates.

At times there are journeys in the mind of an actor that can seem bizarre. I think that deep down, unconsciously, what also played into my preparation for this role were my reminiscences of movies where great American actors like Henry Fonda, James Stewart, and Spencer Tracy played good guys. Simple characters that were honest, modest and clean and whose actions were geared towards doing good. Spencer Tracy, with his eloquence, his silences; even today he is still my favorite film actor. I told Leonardo: ‘I am playing a positive hero.’ I haven’t had any other opportunities to play one, and God only knows how many of them we need today!

Leonardo comes from documentaries. You were in a real jail with real convicts. Did that impact your acting styles?

Orlando: Even more than that it was the reality of this abandoned ancient jail itself that affected me. The empty spaces, the sounds, the smells, the cold. This inhospitable, archaic place made me think how in the end we are still living with a law of retaliation. A place that is supposed to be correctional or educational is instead a place of violence.

Servillo: Yes, the space played a crucial role. The true cruelty of this space; the underground cells. It provided us with a knowledge of this world that we could feed from, to try to get closer to it everyday so we could more effectively portray these characters. In my case there was also the guard’s uniform which for an actor is crucial.

Orlando: On that I will say that when I played Cardinal Voiello [in “The Young Pope”] I was sitting in a hotel lobby waiting to be called to set and two Spanish tourists came, kneeled in front of me and kissed my ring.

Did you guys have fun playing off each other?

Servillo: Yes, it was a lot of fun. It’s a known fact that Silvio has a comic streak, and I haven’t been able to do much comedy on screen, so there was an underlying current of that.

Orlando: But you have natural comic pauses, even though you are known for dramas, and you are really clumsy.

Servillo: Yes, in the kitchen scenes I often bumped my head against the utensils rack and against other stuff.

Orlando: I thought he was doing it on purpose!

Servillo: We had lots of fun. And I think this also gave the film a bit of lightness, where instead it could have become overdramatic.