An ever-so-British dinner party goes ever-so-wrong in ever so many British ways in “The Trouble with Jessica,” a dark but twee comedy of manners.

The “dark” comes from the suicide of a narcissistic, newly-published author who crashes a gathering of old friends to flirt with the married men, insult the women and kill herself as her final act as a troubled and trouble-making attention whore.

And the “twee” spins out of the event itself, friends-since-college who gather for dinner and the host’s famed “clafoutis,” and reactions of the guests — to Jessica’s presence, to Jessica’s ill-mannered man-hunting and to Jessica’s body when she hangs herself in the garden. Those reactions range from shock and grief to self-serving to self-pitying as it seems Jessica has thrown a spanner in the works of a pending and much-needed sale of the posh semi-detached town home where all this takes place.

It’s all feather light and fussy and dash-it-all droll.

Alan Tudyck (“Tucker and Dale vs. Evil,” “Death at a Funeral”) is architect Tom, who preps the meal with wife Sarah (Shirley Henderson of “Greed” and “Miss Pettigrew Lives for a Day”) as audience and sounding board.

They’re having over their oldest friends for one last dinner, finished off with clafoutis, before they sell this lovely, roomy, tony neighborhood/high-priced home.

They met domestic violence counselor Beth — Olivia Williams, “The Father” and Camilla in “The Crown” — and barrister Richard (Rufus Sewell, now in Netflix’s “The Diplomat”) in university.

That’s also where they all met Jessica (Indira Varma of “Rome,””Game of Thrones”), the uninvited guest who tags along with Beth and Richard, much to Sarah’s chagrin. The vaping ex-newspaper columnist Jessica may be enjoying great success, thanks to a sexy memoir just published. But to Sarah, she’s a “narcissicist” who’s “led this life of zero responsibility.” And she always comes-on to Sarah’s husband Tom.

The night will start out testy and go downhill from there, with unfiltered Jessica getting under everyone’s skin, especially Sarah’s, as she holds true to form — flirting with Tom, insulting everybody else by labeling them.

“Charming amoralist” Richard,” “po-faced do-gooder” Beth, “pathological dreamer” Tom and “grown up” Sarah will tolerate only so much from the self-described “f–k-up” Jessica before tempers flare.

And when they do, Jessica skips out to kill herself.

The reactions to this “dilemma” are panicked and exasperated. Only Beth really seems to grieve as the remaining members of the quartet debate the merits of “We’d better call someone” and only Sarah is angry enough at Jessica to consider what this will do to their urgent impending high-value home sale.

The rich “new buyers” (Amber Rose Revah and Sylvester Groth) show up and must be kept in the dark, as will the cops and the fangirl neighbor. The comedy comes from those interlopers and the increasingly edge-of-manic responses by our reserved and out of their depth foursome as they face this “tragedy of the North London elite.”

It’s all utterly predictable, of course — the “What will we do with the body?” debates, obligations and blackmail considerations trotted out, flashbacks to who Jessica was.

First time feature director and co-writer (with James Handel) Matt Winn cast this dinner party with care and leans into the movie’s simple, claustrophobic theatrical structure and assorted twee running gags to make this work.

The repeated phrase “Who DOES that?” applies to killing oneself at a friend’s dinner party, demanding to see a house you’re buying in the middle of the night, etc. The film is divided into cutesie “chapters” including “The Trouble with Neighbors,” “The Trouble with Friends” and “The Trouble with Rich People.”

And nobody involved is neutral on the subject of that overdue dessert, the claofoutis.

As cute and predictable as this all is, the cast hurls itself at this slight farce and makes it play. Tudyck and Henderson, better known as in-demand voice actors these days, are crisply credible as a long-married couple. And Williams and Sewell bring real fire to their fighting each other and Sarah over “the right thing to do” vs. the expedient thing.

Faced with “losing everything,” flipping out and flying into a fury is but one option. The harder one is asking “What kind of people ARE we?” and “Who DOES that?”

Rating: unrated, suicide, profanity

Cast: Shirley Henderson, Rufus Sewell, Olivia Williams, Indira Varma and Alan Tudyck

Credits: Directed by Matt Winn, scripted by James Handel and Matt Winn. A Music Box release.

Running time: 1:29