It’s not the silliest idea ever, taking “The Only Murders in the Building” and making the building Downton Abbey.

“The Thursday Murders Club” is a lighthearted bit of senior sleuthing that takes a prime cut of Britain’s best and most experienced screen actors and turns them loose on a collection of killings.

It’s a genre even older than Dame Agatha Christie. But now it’s “like a true crime podcast,” one character suggests. Because it is. Yes, Richard Osman’s first “Thursday” novel beat the Steve Martin/Martin Short/Selena Gomez streaming comedy to the punch by a year. But the success of one spills over to the other in a film version of “Thursday.”

Given Chris Columbus’s trademark “adequate” direction, but starring a parade of Oscar and BAFTA winners led by Helen Mirren, Ben Kingsley, Pierce Brosnan, Naomie Ackie, Celia Imrie, David Tennant, it’s a minor delight, even if the screen sleuthing here leaves something to be desired.

Mirren, Kingsley and Brosnan play three “OAPs” (old age pensioners) who have found a grand way to pass the time in their posh retirement digs, the estate formerly known as Cooper’s Chase. They dig into cold cases and try to re-investigate, reason out and solve the murders.

A woman’s death in 1973 is the latest murder to earn the attentions of the retired psychiatrist, labor union leader and mysterious “international affairs” specialist (guess who plays what) meet just after the jigsaw puzzle club in one of the drawing rooms of the Downtonish mansion turned retirement home.

They need someone with more medical knowledge to pitch in. Why not the new resident/ex-nurse (Imrie)?

But the rumors that the co-owner of the place (Tennant) aims to close it and redevelop the land — including a cemetery — with high-end housing distracts them. When the mob-connected co-owner who resists this change (Geoff Bell) turns up dead, the club — led by the focused and canny Elizabeth (Mirren) — front-burners this mystery, as their very “to the end of our lives” housing contract and future depends on it.

The plot ensares a traffic cop (Ackie) whom the club finagales a promotion to Criminal Investigation Division to help the always-eating Detective Inspector (Daniel Mays of “Vera Drake” and “Fisherman’s Friends”) and folds in literal cemetery plots and long-on-the-lam gangsters (Richard E. Grant).

The cast includes the original Indiana Jones foil (Paul Freeman), one of the mainstays of Mike Leigh’s repertory company (Ruth Sheen) an ex James Bond and a Bond villain (Jonathan Pryce).

The japes, leading the cops around by the nose, play acting and playing up their turns as elderly fussbudgets — “Is it HOT in here?” “I’m a 76 year old woman. Of COURSE it’s hot!” — all lean into cute. Their director, who did “Home Alone” and the early Harry Potter pictures, knows all about cute.

So when Mirren’s Elizabeth dresses down for an outing, her mentally-slipping onetime writer husband (Pryce) blurts “You look just like the QUEEN.” Which she does. Because Mirren won an Oscar playing another “Elizabeth.”

The players are the reason to relish this bon bon, with Kingsley in fine fidget, Brosnan all Irish leftist bluster and Mirren giving a comic edge to a performance that harks back to her “Prime Suspect” past.

It isn’t Hulu’s “Only Murders in the Building,” which is just as star studded but funnier, a chatty, podcast-dependent cliffhanger series. But if you like your mysteries tidied up in feature film form, “Thursday Murders Club” will do.

As with Dame Agatha’s Greatest Hits, are more “Thursday” books about these sleuths, so maybe they’ll give us more.

Rating: PG-13, violence, profanity

Cast: Helen Mirren, Ben Kingsley, Pierce Brosnan, Celia Imrie, Naomie Ackie, Daniel Mays, Ruth Sheen, Paul Freeman, Henry Lloyd-Hughes, Geoff Bell, Jonathan Pryce, Richard E. Grant and David Tennant.

Credits: Directed by Chris Columbus, scripted by Katy Brand and Suzanne Heathcoate, based on a novel by Richard Osman. A Netflix release.

Running time: 2:00