There have been 13 popes named Leo in the history of the Roman Catholic Church, but perhaps none of them was as famous as the Leo who entered the Vatican today (28 January 2016): Hollywood star Leonardo DiCaprio. Oscar-nominated DiCaprio was received by Pope Francis and treated to a 15-minute audience with the pontiff. "Your Holiness, thank you for giving me this private audience with you," an unusually nervous-looking DiCaprio said in Italian after kissing the pontiff's hand.

The Revenant star handed a book showing the drawings of Dutch artist Hieronymus Bosch to the pope as a gift, explaining that his father had hung a picture of one of the works above his bed as a young boy. Bosch is known for his colourful imagery that often portrayed landscapes and religious concepts.

"It was hanging above my crib as a young boy. My father put it there. And as a child I didn't quite understand what it all meant, but through my child's eyes it represented our planet – the utopia that we have been given," he said. After leafing through the pages of the book in front of the Pope, DiCaprio said: "It represents to me the promise of the future and enlightenment, and it is representational of your view here as well. I wanted to give you this book as a gift."

Before the film star left the papal chamber, Pope Francis handed DiCaprio a copy of his encyclical on the environment and said: "Pray for me, don't forget."

Last week, the 41-year-old Oscar nominee was honoured at the 22nd Annual Crystal Awards held at the World Economic Forum in Davos, Greece for his foundation's support of conservation and sustainability projects.