“Shotgun Wedding” is a chocolate-covered cherry with liqueur inside. It starts as a glossy but merely serviceable romantic comedy about a couple who both have jitters the night before their big day. Then the sun comes up, and the movie turns into an action comedy: the heroine and her fiancé try to save their parents and the rest of their wedding party from pirates who have invaded their nuptials on a tiny island near the Philippines that is conveniently (for plot purposes) too far from the mainland to get good cell reception.  

Jennifer Lopez plays the bride, Darcy, who didn’t want to have a big wedding but agreed because … well, maybe it’s best to leave that to the film to explain. There are also the concerns of Darcy’s fiancé Tom (Josh Duhamel), a washed-up minor-league baseball player; the insinuating entitlement of Darcy’s ex-lover Sean (Lenny Kravitz), who wasn’t invited but showed up anyway; the awkward energy of Darcy’s divorced mom and dad, Roberto and Renata (Cheech Marin and Sônia Braga), which informs the bride’s anxieties; and the sprightly middle-American cluelessness of Tom’s parents Carol and Larry (Jennifer Coolidge and Steve Coulter). 

Coproduced by Lopez’s company, “Shotgun Wedding” is a ludicrous fantasy occurring in the universe of movies. The stunts are straight out of an Alfred Hitchcock thriller or James Bond picture. But we’re willing to accept the silliest situations because the emotional currents that flow between the main couples are grounded in the messiness of life. (Darcy and Tom have a recurring, irresolvable argument over how many steps in a plan are too many that might make some viewers feel eavesdropped on.) At first, it seems as if the pirates will be faceless Pacific cannon fodder, but amusing characterizations and subsequent plot twists upend that concern: everyone in this film is a bit of a kook, including the bad guys. As in hard-edged Hollywood comedies like “Game Night,” the violence goes up to the edge of unpleasantness while staying in cartoonland.

Lopez and Duhamel are both probably too old for roles that show signs of having been written for twentysomethings. Lopez, 52, projects an ingenue’s energy and insists, “I’m a grown woman!” Duhamel, 50, is as old as the oldest active Major League Baseball player, and we’re supposed to accept that he was being scouted a year before the film’s events. But the performers are such fierce comic presences that we accept them as a couple of lovable kids who have a lot to learn about relationships.

Lopez puts her physicality to great use. In the first part of the movie, Darcy, clad in a tank top and undies, “tries” and “fails” to reach a book on a high shelf to flirt with her stressed-out fiancé (this is part of their bedtime roleplaying routine; he’s the hunky handyman). It’s naughty and funny in the way that actual flirting can be. Later, there’s a stunt that is to long bridal trains what the end of “The Incredibles” is to superhero capes. It’s followed by a poster-ready moment where a shotgun-toting Darcy’s previously encumbering gown gets shredded in a way that makes her look like a sci-fi bounty hunter. Duhamel uses his action-hero body and oak-aged bourbon voice in a wounded way. His Tom is giant little boy who lives in fear of being a disappointment. But once explosives go off and golf carts tumble from cliffs, the character’s filthy, blood-spattered tuxedo brands him as a stalwart action hero: Bond’s low-self-esteem Yankee cousin.

Screenwriter Mark Hammer and filmmaker Jason Moore (a film and TV veteran who directed “Avenue Q” and “Steel Magnolias” on Broadway, as well as “Pitch Perfect”) have a sure touch with their leads and get sharp supporting performances from the secondary cast. Coolidge steals the movie as she always does: by blurting out surreal, nonsensical things at inappropriate moments. Marin is also superb in a role that calls for underplaying (he gets some of the film’s biggest laughs by repeating two words: “Thanks, Carol”). Braga’s part is underwritten (or perhaps got cut down?), but she uses her otherworldly gaze to suggest that the character keeps secrets she’ll never share. Kravitz is another standout, playing a preening chunk of beefcake who thinks he’s God’s gift and is good-looking enough to keep failing upward. It’s like George Clooney’s performances for the Coen Brothers where he takes the piss out of himself for being so handsome.

The movie hits many beats you’ve seen and some you haven’t. The first act, in which the guests arrive on the island (Sean descends via helicopter, shirt open to his navel) and Mark Hammer’s screenplay sets about introducing then all, is brief. But it feels endless, owing to exposition as blunt as the name tags that come into play later in the story, as well as catchphrase-laden lines that are too Hollywood-writers-room (like “Dad is a messy bitch who loves the drama” and “Pirates chasing you wasn’t on your vision board?”).

But to be fair, even a few of the great rom-coms struggle to get that sort of thing out of the way—and once the pirates state their demands, the movie is, to quote guru screenwriter William Goldman, on rails, gliding from one set piece to the next, infusing brawls, shootouts and other mayhem with odd sweetness. Along the way, it showcases a gift that’s become sadly rare in American commercial cinema: the ability to invest ordinary objects—a bridal gown, a tuxedo, a cake knife, name tags, wedding invitations, a shotgun, a grenade—with a dash of poetry. There’s a shot of a speedboat that you wouldn’t expect to pack an emotional punch, but it does by that point in the story. The filmmaking is efficient and sometimes sublime. There’s a music montage near the end where sound and dialogue drop out and we’re just watching bodies move through space, slow-mo action-film badassery fusing with goofy comic bits. It’s thrilling, not just because it’s elegantly directed and cut (by editor Doc Crotzer) but because Lopez and Duhamel seem to have made a pact to pretend they’re starring in “The Last of the Mohicans.”