This image is from the official trailer for “I Want You Back,” distributed by Prime Video.

When it comes to films, I’m a comfort rewatcher before anything else. There are six or seven movies I keep in constant rotation, and I put them on whenever I want my brain to quiet down a bit. They don’t have to be my favorite movies — they don’t even have to be objectively good — but they’re dependable and fun and usually have killer soundtracks and invariably beautiful casts. Among them: “Someone Great,” “Sleeping with Other People” and “Set It Up.” Rewatchability, thy name is rom-com.

Halfway through “I Want You Back,” Prime Video’s newest addition to the genre, I could feel my brain placing it in that rotation. With two eminently charming (and relatively unconventional) leads in comedy veterans Jenny Slate (“Obvious Child”) and Charlie Day (“It’s Always Sunny in Philadelphia”) and just enough subversions of well-worn tropes, the film is actually, genuinely funny, and it manages to feel fresh even as it works within the confines of a familiar structure.

For one thing, there’s a meet-cry in place of the meet-cute. Having just been broken up with by Noah (Scott Eastwood, “Pacific Rim: Uprising”), her boyfriend of 18 months, and Anne (Gina Rodriguez, “Jane the Virgin”), his girlfriend of six years, Emma and Peter meet in the stairwell of their shared office building, which they’ve both retreated to in order to do some ugly sobbing in private. After bonding through their shared circumstances, they hit it off, do drunk karaoke together and decide that they’ll be “sadness sisters” in order to keep each other from calling their exes, who are already in relationships with other people. But as they grow closer, they concoct a new plan: Peter will befriend Noah and convince him to take Emma back, and Emma will seduce Anne’s new boyfriend Logan (Manny Jacinto, “The Good Place”) to break them up.

I don’t want to sound like Dave Franco, who’s producing what he (pretentiously) describes as an elevated rom-com, because I like rom-com conventions, even if they are played out. But, there is something a little different about “I Want You Back.” It’s not that it completely rejects the traditional form or style of the rom-com; rather, it just does both really well. There is, of course, a moment when Emma steps out of a dressing room, and Peter can’t help but stare. There is, of course, a conversation between them about what love looks like and a predictable but still satisfying callback to it at the end. There is, of course, a montage and an unnecessary (but delightful) musical number. I can name at least three other movies that do any combination of at least two of those things, but the reasons why they feel refreshing in “I Want You Back” have everything to do with Slate and Day.

While the pair’s romantic chemistry isn’t immediately apparent, their comedic chemistry is. A movie created by the writers of “Love, Simon” and “This is Us” (Isaac Aptaker and Elizabeth Berger) could have easily fallen into self-seriousness, a saccharine sort of sappiness and just a hint of outdatedness, but it’s clear that Slate and Day were given room to play off of each other and just have fun together, which grounds the movie and makes its admittedly pretty outlandish narrative feel more organic. It’s so easy to buy them as new friends, best friends and then a hint of more. It’s no surprise that the film struggles more in its second half, when circumstances dictate that Emma and Peter spend less time together.

Slate, Day, a charming supporting cast and a couple of genuinely surprising narrative choices and emotional beats make “I Want You Back” an incredibly easy watch, one that’s perfect to throw on TV this Valentine’s Day and one that I’ll be revisiting at least three times a year.

Senior Arts Editor Katrina Stebbins can be reached at