Veteran movie stars Diane Keaton and Jude Law have been tapped to move over to the small screen in a new HBO series called The Young Pope, reports Variety.

In the series, which will run with eight episodes, Law will play the title role of Pontificate of Pius XIII (Lenny Belardo), who faces hardships along his path toward following God. Keaton, meanwhile, will play Sister Mary, an American nun residing in Vatican City.

The show begins production this week, and will be directed by creator Paolo Sorrentino and produced by Sky, HBO, and France's Canal Plus. Sorrentino has already built a name for himself in the movie business, most notably having won the Oscar for Best Foreign Language Film at last year's ceremonies for his 2013 film, The Great Beauty.

Sorrentino describes the series as looking at "how faith can be searched for and lost. The greatness of holiness, so great as to be unbearable when you are fighting temptations and when all you can do is to yield to them."

Interestingly, this will be the first time Keaton takes on a starring TV series role in her 45+ years in the business, though she has appeared in a few TV movies and miniseries, including 1977's The Godfather: A Novel for Television as Kay Adams Corleone.

Law is also mostly known for movie roles, including his roles as Dr. John Watson in Guy Ritchie's Sherlock Holmes films, Gigolo Joe in A.I. Artificial Intelligence, and as the voice of Lemony Snicket in Lemony Snicket's A Series of Unfortunate Events.

The Young Pope will mark the first show co-produced by both HBO and U.K. broadcaster Sky, which may have something to do with the mix of American and British stars at the helm, thus appealing particularly to both markets. The two have a deal whereby Sky has exclusive rights to HBO programs in the U.K.