Fonda. Bergen. Keaton. Steenburgen. “Book Club.” Sure, “Avengers: Infinity War” came out a few weeks ago, but this, now this is the greatest crossover event in history. Four of the most iconic actresses of the 20th century come together for a film in which their book club reads “50 Shades of Grey”? When can I line up?

This film is either in your wheelhouse or it’s not, but for those looking forward to “Book Club,” it delivers. For what it is — a breezy bit of Nancy Meyers-lite fantasy, featuring four beloved actresses talking about sex, baby — it’s exceedingly enjoyable. But beyond its shiny surface and real estate pornography, the film, directed by Bill Holderman and written by Holderman and Erin Simms, is a way to talk about the ways in which older people are desexualized in our culture. And it’s rallying cry against that trend, which is in many ways a dehumanization.

That they get there through E.L. James’ tortured pop-erotica prose is pretty silly, but at least the characters have some perspective on the questionable quality of the “50 Shades” trilogy, and we don’t have to delve too deeply into the world of Anastasia Steele and Christian Grey’s red room. The books simply serve as a stimuli for the women to explore their own sexuality in a world that often wants to deny that.

Each actress is given a role that hews closely to her own persona, so the performances aren’t necessarily anything we haven’t seen before. Fonda plays a wealthy, age-defying hotelier, Vivian, fond of her independence and thigh-high boots, currently entertaining a younger lover from another era, Arthur (Don Johnson). Diane Keaton plays the hilariously high-strung Diane, a recent widow and the mother of two wildly condescending adult daughters (Alicia Silverstone and Katie Aselton) pressuring her to move to Arizona to play grandma. Steenburgen is Carol, a chef and devoted wife to Bruce (Craig T. Nelson), trying to put some spark back into their 30-year marriage.

But it’s Candice Bergen that steals the whole film, playing a long-divorced, no-nonsense federal judge, Sharon, exploring online dating for the first time since learning of her ex-husband’s young new fiancee. Everything Sharon does is wonderfully relatable, from her one-liners about professional ice cream eating to her Bumble profile pic, an accidental selfie complete with green face mask and upside-down glasses. Her dry wit is an essential grounding element in the film that could otherwise be far too flighty to take seriously. In fact, what we deserve is a Sharon stand-alone in the “Book Club” cinematic universe, just 90 minutes of her awkward dates and drinking white wine with her cat, Ginsberg.

Each subplot is rather perfunctory, but it’s lovely to see a film where older women are wined, dined and courted by somewhat younger men. It may be fantasy, but that Hollywood would even dream up a bit of escapist fluff where Andy Garcia romances Diane Keaton is refreshing. The fact that her sexiest scene involves being covered from head to toe in a bathrobe and floppy hat is just so Keaton.

The ultimate message of “Book Club,” beyond asserting the vitality, sexual appetite and humanity of older people, is everyone, of any age, who feels stagnant or stuck in their ways, has the opportunity, nay, the responsibility to shake it up and put themselves out there. Which is even a heavily sanitized version of the message of “50 Shades.” “Book Club” just might be the best adaptation of that book series yet.

If you go

BOOK CLUB

PG-13, 104 minutes

Playing at Niantic, Madison Art Cinemas, Mystic Luxury Cinemas, Waterford, Stonington, Westbrook