The movie veteran is thrilled to be playing the Catholic Church's late leader.
He says, "He had real faith and real fervour. He was a man of God... He was a real moral leader in an important time.
"I'll only get one shot at it. I better do a good job."
Meanwhile, Elwes reveals he has special memories of the Pope - he met him shortly before he died earlier this year (05).
He recalls, "That spirit that I came away with from having met the man is something that I've been constantly working on to infuse the character with."
The miniseries, POPE JOHN PAUL II, follows the pontiff's life from a young anti-fascist activist in pre-war Krakow, Poland to his death.