Richard E. Grant and Tom Ellis have joined the cast of 'The Thursday Murder Club'.

The duo are the latest additions to an all-star ensemble for the film adaptation of Richard Osman's 2020 crime novel of the same name.

The pair join a line-up that includes Dame Helen Mirren, Pierce Brosnan, Sir Ben Kingsley, Celia Imrie, David Tennant, Sir Jonathan Pryce, Naomi Ackie, Daniel Mays and Henry Lloyd-Hughes.

Other new cast members include Geoff Bell, Paul Freeman, Sarah Niles and Osman's wife Ingrid Oliver.

The Netflix film is being written and directed by the 'Home Alone' filmmaker Chris Columbus and follows a group of four friends in a retirement home who gather to solve murders for fun but end up getting embroiled in a real case.

The quartet are played by Mirren (Elizabeth), Kingsley (Ibrahim), Brosnan (Ron) and Imrie (Joyce).

‘The Thursday Murder Club’ started a hugely successful series of books from Richard that have sold more than 10 million copies worldwide - including ‘The Man Who Died Twice’, ‘The Bullet That Missed’, ‘The Last Devil to Die’ and a planned fifth novel which is set to be released next year.

Osman has waxed lyrical about the casting and suggested that it is the strongest group of British actors to be assembled since the 'Harry Potter' movies.

Speaking on his 'The Rest Is Entertainment' podcast, the 'House of Games' presenter said: "There’s some great names and some more names coming as well.

"I think this is the greatest British cast assembled since the [‘Harry Potter’] movies."

Richard, 53, previously revealed that he had long harboured a desire to pen a crime novel.

He told The Guardian newspaper: "I've always known how hard it is to write a crime novel and I have such respect for people who do it. I never felt I was in a position where I could do it properly and give it the time it deserved until about 18 months ago.

"I decided I would start it and once I got going I found that I couldn’t stop. But I decided I wasn’t going to tell anybody because I didn't want to be that person who goes around saying, ‘Oh yeah, I'm writing a book’, but it never happens.

"When I got to the end I thought, well, there at least I’ve found out that I can do it. But I had no idea what people would make of it."