The filmmaker will start working on the true-life religious drama after he wraps the sci-fi thriller "Ready Player One," reported Variety.
Tony Kushner is adapting the script based on David Kertzer's novel.
The true story centers on a 6-year-old Jewish boy in Bologna, Italy, in 1858, who was seized by the police and removed from his parents' home. He was subsequently raised as a Catholic and became a priest in the Augustinian order. Rylance will star as Pope Pius IX.