Al Pacino and Dan Stevens have been cast in 'The Ritual'.

The duo will play troubled priests in the exorcism horror film from director David Midell.

XYZ Films have acquired worldwide rights to the project – which is based on a true story and has been written by Midell and Enrico Natale - and are planning to release it in cinemas in 2025 and arrange international distribution at the forthcoming Cannes market.

'The Ritual' follows a pair of priests – one who is questioning his faith (Stevens) and another reckoning with a troubled past (Pacino) – who have to put their differences aside to save a possessed young woman through a dangerous series of exorcisms.

The flick is an authentic portrayal of Emma Schmidt, an American woman whose demonic possession concluded with harrowing exorcisms.

Dan, 41, is coming off the back of a part in the monster movie 'Godzilla x Kong: The New Empire' and had a "ton of fun" making the film with director Adam Wingard and his co-star Rebecca Hall.

He told Entertainment Tonight: "It's an incredible call to get at the best of times, but to get it from an old friend, Adam Wingard, who directed the last installment of these, to join Rebecca Hall, who is one of my oldest buddies, Brian Tyree Henry, who I adore - and they wrote me an incredible character.

"So, you know, it was just a ton of fun."

Dan rose to fame as Matthew Crawley in 'Downton Abbey' and is "excited" about the prospect of a third movie, even though he bowed out of the TV series after season three.

He said: "Like with any show where you're in people's living rooms on a Sunday evening, you know, people take a special kind of ownership of that.

"They become a part of your family in a way. You sit down, you watch it with your mom, your grandma. So many people I know have seen that show, and it's really brought families together.

"We laugh, we cry, but, you know, it's one of those shows where it means a lot to a lot of people.

"So I'm excited for another movie."