David Suchet has extracted plenty of confessions in his 25 years as TV detective Hercule Poirot but his first stage play in Perth is an entirely different whodunit.
Suchet leads an international cast of 20, which includes WA actor Andrew Hale, in Roger Crane's robe-and-dagger drama The Last Confession.
The play acts out the murky circumstances about the controversial death of Pope John Paul I just 33 days after he was appointed in 1978.
Suchet appears as Cardinal Giovanni Benelli, who helped install the Pope and sets out to find the truth after other Vatican officials refused to investigate.
The British actor said audiences should not be deterred by the religious setting because the play was a riveting political thriller whose backdrop happened to be the Catholic Church.
"One of the great things about this play is that audiences coming to it who know nothing about the history of what happened, are suddenly confronted on stage with people like me walking around dressed like this and they may think, 'Oh gosh, have we come to a religious play. It's called The Last Confession, what is it? We know David Suchet is in it and we like him as Poirot', but then they forget and they are drawn into the world of the Vatican and it has got nothing to do with religion at all.
"This has to do with power and politics."
"Although the Vatican closed the doors on this particular situation, this play has opened the audience's mind to the intrigue and possibility of what was going on.
"I'm here to tell you I wouldn't be in a play if it was just about religion and the Catholic Church. This is a play about one of the monumental crises of the 20th century. It was huge. It could have brought down the whole of the Catholic Church. It was that big."
"We don't actually point fingers but the story obviously created a taint around the Roman Catholic Church at the time."
Suchet said senior Catholic clerics who saw the play in Canada had told him they had been intrigued, entertained and gripped by the play about a mystery that would never be solved.
One reviewer has described The Last Confession a hybrid of Poirot and The Da Vinci Code.
After an acclaimed 45-year career on the stage and screen, including 74 episodes of Agatha Christie's Poirot, Suchet said he still felt an extraordinary buzz when he stepped onstage in a live theatre.
"That has never changed in however many years I have been doing the job," he said. "Backstage, your heart is fluttering, you don't know if you are going to remember every line. It is ridiculous. I have been doing this for more than 40 years.
"You just want to do your best for the play and for your audience. So many people out there have spent so much money to see this play and if you are playing the lead, the responsibility is huge and you want to get it right for everyone.
"That sense of excitement and thrill never ever leaves you."
The Last Confession has a cast of 20, an unusually large number for a conventional stage drama.
Hale said he was delighted to have been cast in an international production that has recruited actors from the Canada, Britain and Australia.
The Perth actor had filmed his audition on his phone and sent the footage to the producers in London.
"That is turning into the new way of doing it," he said. "I quite like it. There is no pressure because you can do it until you are happy with it and send it off."
The production was a significant step up from grafting a career writing and performing his own shows as an independent artist in Perth, Hale said.
"It is really lovely to be involved in such a large cast. This is all about bitching and infighting and backstabbing in the Vatican. What is marvelous about this cast is that this all happens on stage and off stage everybody is just magnificent and a lovely cast to be involved with."
The Last Confession runs until August 16 at His Majesty's Theatre before touring the east coast until October.