Coarse, crude but often cute, “The Big Wedding” serves up the spectacle of its title, and the bigger spectacle of four AARP-eligible Oscar winners cursing like sailors.

A teasing sex farce littered with F-bombs and C-words, it’s the filthiest (sounding) movie of the year — so far.

Justin Zackman’s adaptation of the French comedy “Mon frere se marie” benefits from old pros Diane Keaton and Robert DeNiro, Susan Sarandon and Robin Williams, all  playing cynics  conspiring or blundering into butchering the wedding of poor Melissa (Amanda Seyfried) and Alejandro (Ben Barnes).

Let’s face it, you don’t quote Oscar Wilde to a couple who plan to wed.

“Marriage is the triumph of imagination over intelligence.”

Alejandro’s the adopted Colombian son of Don (DeNiro) and Ellie (Keaton). Only they’re divorced.

Don, a swaggering “little blue helper” loving sculptor, lives with Bebe (Sarandon), who cheated with him over a decade ago. But now Ellie is back for the wedding, and Alejandro’s long-absent,unbendingly Catholic birth mother (Patricia Rae), who is already putting them through the ringer with the seriously narrow-minded priest (Williams), won’t understand how divorced parents can have raised her boy to know what marriage should be.

So Don and Ellie pretend they’re still married. Bebe, hurt, flees — but doesn’t. After all, she’s planned the wedding, so she’ll just hang with the caterers. Don is on the wagon. For now. And Ellie may still have the hots for him.

Then there’s Alejandro’s step-sister Lila (Katherine Heigl), split from her husband and resentful of the father who expects them to bond in some some of “father-daughter Kumbaya on a stick” moment. And Jarod (Topher Grace), their virginal doctor brother (Topher Grace) meets Nuria (Ana Ayora), Alejandro’s oversexed Colombian sister, who promptly strips, skinny dips and hurls herself at poorJarod.

What could go wrong?

“Big Wedding” has a witty script — even the occasional subtitled bit tickles — that wears its French origins well, and the players are — to a one — a pleasure to watch, from the testy-sexy turn by Keaton, to a perfectly wounded Sarandon, with randy Robby DeNiro letting his eye wander from one to the other. Heigl, Grace and Williams, not having to carry the picture, give relaxed performances that play to their “types” And their strengths. Christine Ebersole has a chewy scene or two as Melissa’s bigot mom, worried about the “beige babies” that will come from such a union.

The young couple are mostly just an excuse for everybody else to let rip, though Harvard grad Alejandro is seriously put off by the priest’s probing questions — about premarital sex.

“I guess I’m going to hell, then.”

“In God’s good time.”

Birth control?

“Hell it is, then.”

The best wedding comedies — “My Best Friend’s Wedding” is still the gold standard — keep emotions close to the surface and a song on everybody’s lips. “Big Wedding” does OK by the music, but pretty much blows the emotional bits.

And it never quite works itself into a farcical lather. But much of the one-liners and insane situations land; the bullying Catholic mom demanding that everybody — non-believers one and all — take confession, which they do, in the most uncensored terms imaginable. Wedding dinners and pre-ceremony fights are filled with jaw-dropping revelations and embarrassing stumbles.

That’s almost too much to pack in an old-fashioned, new-profanity R-rated romp, a gentle, older-skewing comedy that would have been far less jarring as a PG-13.