This brand new eight-part HBO series follows the story of a fictional American-born pope played by Jude Law. Yeah... Jude Law as pope? We're not sure if we're buying it either but HBO rarely lets us down in fairness. It also stars the legend that is Diane Keaton in what is her first regular role for TV. The Oscar-winning actress is set to play an American nun living in the Vatican City. Tonight's opening episode kicks off with the world's youngest Pope taking up residency in the Vatican where he struggles to establish his papacy.