Of course an actor like Hugh Bonneville would be captivated by the drama of the last week of Jesus’ life, with his triumphant entrance into Jerusalem, his challenging of the priests in the temple, his betrayal by Judas and his sentencing to crucifixion at the hands of a mob.

What will surprise many is that Bonneville, 54, whose biggest role to date has been as Lord Grantham in “Downton Abbey,” has a theology degree from Cambridge University, where he was taught Christian history by Rowan Williams, formerly the archbishop of Canterbury, the head of the Church of England.

After Cambridge, Bonneville went on to drama school, but last year he packed a suitcase full of his old Cambridge textbooks and headed for Jerusalem to research and retrace the last tumultuous days of of Jesus’ life. The result is a new hourlong documentary, “Jesus: Countdown to Calvary,” which will air on most public television stations before Easter.

“This is a place where history and faith come together,” Bonneville says in the opening section of the documentary, standing before the sunny, heat-kissed stones of the old city. “Whether you are a person of faith or of none, you cannot escape the fact that the last six days of this man’s life, and his death, changed the world.”