VATICAN CITY (RNS) — In a new documentary produced in collaboration with the Vatican, actor Chris Pratt and Pope Leo XIV venture into the secret catacombs under St. Peter’s Basilica, exploring how the long-lost remains of the first apostle were found.

“Pétros ení: Discovering the Origins” premiered Friday (Oct. 16) at the Rome Film Festival ahead of the 400th anniversary of the consecration of St. Peter’s Basilica next month. It was released in Spain on Oct. 9 and is expected to be available widely in early 2027.

The roughly one-hour documentary was produced by AF Films in collaboration with the Vatican Dicastery for Communications and the Fabric of St. Peter, an organization tasked with maintaining the basilica. Pratt serves as narrator. 

Beyond the archeological discoveries, the film explores how the church was handed to Peter, an imperfect man who became one of Christianity’s early leaders. That theme holds significance today as Pope Leo XIV recovers after lung surgery to treat cancer.

“What I would like audiences to understand about Peter after watching this documentary is that he was an imperfect man. He was a weak man. He was a human being,” Pratt said in a short video introducing the film at the premiere.

“I believe we are all broken, imperfect and weak,” said Pratt, known for his roles in films like “Guardians of the Galaxy” and the television comedy “Parks and Recreation.” “But (Peter’s) strength lies in the grace of Jesus and his faith in God. With that strength, through grace and faith, you can be incredibly strong.” 

Pratt, who was raised Catholic, said in the video that he typically distances himself from religious institutions and tends to “find God in the woods.” But he said the experience of bringing a camera crew into the heart of the Vatican, where the basilica is located, was a “deeply personal” moment for him. “It has drawn me in,” he said.

The head of the Vatican Dicastery for Communication, Paolo Ruffini, addressed the “Christian paradox” of “a church that Jesus entrusted to the leadership of a weak and sinful man,” in his introductory remarks at the premiere.

The first shots of the documentary show Pratt walking the steps of an ordinary pilgrim to the Vatican. His journey then takes him deep beneath St. Peter’s Basilica, which is rarely trodden by its roughly 45,000 visitors every day.

Spanish director Paula Ortiz, best known for “The Bride” and her drama about St. Teresa of Ávila, “Teresa,” said at the premiere she hoped the documentary could show how St. Peter’s Basilica “defines and crystallizes our civilization.”

The new film “Pétros Ení: Discovering the Origins” features Chris Pratt and the pope in a conversation around St. Peter’s tomb. Cover art courtesy Vatican Media

In harmony with Pope Leo — whose first major teaching document, “Magnifica Humanitas,” warned against the dangers of artificial intelligence — the documentary specifies it did not use AI in its making.

Sweeping shots and camera effects match the theatrical quality of the basilica’s Renaissance art, rich in surprises, reveals and larger-than-life figures that could easily rival the modern superhero movies in which Pratt has starred. At times, the film channels the Vatican intrigue of Dan Brown’s “Angels and Demons” movies, though its repetitive, ornate narration slows the adventure.

The new film “Pétros Ení: Discovering the Origins” features Chris Pratt and the pope in a conversation around St. Peter’s tomb. Cover art courtesy Vatican Media

Books and blog posts have speculated about ancient secrets that may lie beneath the Vatican. The documentary covers some of them via stones, relics and ancient writings that unveil the almost forgotten history of the burial of St. Peter.

In 1939, Pope Pius XII ordered an excavation beneath St. Peter’s. In 1941, workers became the first to enter the well-kept remains of the ancient Roman burial ground in over 1,600 years.

Workers at the time thought they had found the ancient burial site of St. Peter, but there was no trace of his remains. Pietro Zander, a leading expert on the necropolis, leads viewers through the mystery of Peter’s remains. It would take 10 years for epigrapher Margherita Guarducci to interpret an inscription “Petrus Eni,” or “Peter is here.”

Workers later found a wooden box containing human remains believed to belong to a man in his 60s, which matches Peter’s age at death. It was also found the remains were missing feet.

According to Catholic tradition, St. Peter was crucified upside down in the circus made by emperor Nero that once towered over Vatican Hill at a time of relentless persecution of Christians. According to historians, the remains of the first apostle were thrown in the ground with many others before being salvaged, wrapped in expensive cloth and stowed away to be secretly venerated for centuries.

In 1968, Paul VI announced that the relics of St. Peter were found.

The documentary closes with Leo descending toward Peter’s burial place. “When we look at the splendor of St. Peter’s and the colonnade that opens its arms to embrace the world, it is good to remember why this basilica was built right here,” the pope says, looking straight to the camera. “The reason is that this ground is soaked with the blood of the apostle.” 

“This is how, link by link, that fragile chain of Peter’s successors has reached us,” he says. “And I, too, bishop of Rome, aware of my weakness, repeat the profession of faith of the apostle whom Jesus transformed into a fisher of men: ‘Yes, you are the Christ, the Son of the living God.’”