Jude Law as the Pope? The actor and famous lothario, who was dubbed People magazine's Sexiest Man Alive in 2004, knows he is an unlikely choice to play the head of the Catholic Church in a new television show, The Young Pope.

Written and directed by Oscarwinning Italian film-maker Paolo Sorrentino, the show imagines the cut-throat world of Vatican politics. It airs in Singapore on the FX channel (StarHub TV Channel 507 and Singtel TV Channel 310) on Mondays at 10pm.

Law is Lenny Belardo, a former archbishop of New York who ascends to become Pope Pius XIII, the first American pontiff.

After appointing Sister Mary (1977 Annie Hall's Diane Keaton), the nun who raised him in an orphanage, as his personal secretary, the new pope proceeds to shock and confuse the clergy and laity with his unorthodox ways, all the while struggling with his past and his own faith.

Speaking to The Straits Times and other press in Los Angeles last week, the 44-year-old British star - who turns up looking distinctly unpope-like, sporting a natty blazer and deep tan - admits he once would have scoffed at the prospect of playing the pontiff.

"If you'd asked me two years ago, I would have laughed at the idea," says Law, who has five children, aged one to 20, with three women.

"But I was just very keen to work with Paolo and I think I'd have probably jumped at any opportunity. It just so happened that he was also coming up with this extraordinary part and imaginative world."

Sitting next to him, 46-year-old Sorrentino - who won the Best Foreign Language Film Oscar for The Great Beauty (2013) - is asked why he did not draw from real Vatican politics and current events, and instead dreamt up this hyperreal drama.

"Because it could be possible that after Pope Francis, the next Pope could be somebody like the character of Jude Law. This is the thing that many experts in the church told me. And so the idea was to do a sort of future Pope."

As well as being a mess of contradictions - ruthless yet melancholy, doubting yet determined - Pope Pius XIII is also shown to have several vices, among them a fondness for cigarettes.

Such details make the world of the show such a rich one, says its star.

"I believe it was inspired by Pope Benedict, who apparently liked a cigarette after mass. And it was, I thought, a wonderful detail of character that Paolo included. His scripts are rich with detail of both musical references and character references.

"For an actor, that's joyful. You sink your teeth into those," says Law, who earned Oscar and Golden Globe nominations for The Talented Mr Ripley (1999).

The series is not meant to be a satire of the Church or politics as much as it is a character drama, says Sorrentino. "The subject is mostly about the solitude of power - the solitude of the man and the loneliness of being a person with big questions about the existence of God and what God is for us."

For Law, humanising a largerthan-life figure in this way is what Sorrentino does best.

"One of the reasons I love Paolo's work is that he can take epic themes and operatic scale and make it very human," says the actor, who has appeared in acclaimed dramas such as Gattaca (1997) and Closer (2004).

"When I was preparing for this part, I initially started thinking, 'Gosh, I need to educate myself on papal history, on Catholic history, on life in the Vatican.'

"But I didn't really find any answers as to who this character was and Paolo kept reminding me that, really, I had to concentrate on who Lenny Belardo was. And Lenny is an orphan and, in his heart, is trying to understand this sense of a lack of love.

"A lot of the part he plays as Pope Pius is trying to understand that and his sense of solitude through his power. But the vulnerabilities are there and, I hope, slowly unpeeled if you stick with the 10 hours."

Law says the role was particularly eye-opening, given that he "wasn't brought up in a particularly religious household".

"But I've always been curious about faith and one's personal relationship with faith. And I suppose it encouraged me to question and look at that a little more."

• The Young Pope airs in Singapore on FX (StarHub TV Channel 507 and Singtel TV Channel 310) on Mondays at 10pm.