I Want You Back will make your heart ache for Jenny Slate and Charlie Day. That has nothing to do with the characters they play or the story they’re put through, which takes pains and padding to try to reduce the overt predictability of this routine romantic comedy. No, you will feel bad for the actors for this movie being the best offer they had on their tables.

Slate and Day have entertained us for years. They both got their starts on television. He’s been the most lovable in the band of misfits who have kept “It’s Always Sunny in Philadelphia” running for nearly twenty years now. She was briefly on “Saturday Night Live” and graduated to an assortment of recurring roles. They both made their way to the big screen. Day shined as comic relief and as the standout third of the winning Horrible Bosses protagonists. Slate drew acclaim and a scattering of breakthrough performer awards as the star of 2014’s Obvious Child. They both elevated animated movies with spirited vocal performances in films like Zootopia (her) and The Lego Movie (him). And now they find their considerable talents coming together for that most banal of big screen comedy, the February romcom.

Sparing this R-rated movie of poor box office performance reports and pandemic concerns while greatly expanding its immediate audience at no immediate economic impact, Amazon Studios puts this on Prime right away beginning on February 11th. Whereas movies like Netflix’s The Irishman, Roma, and The Power of the Dog feel too big to be watched primarily on streaming services from the get-go, I Want You Back should feel a lot more at home being half-watched in a living room than it was at my screening, projected on the big screen, a majority of its jokes dying loudly at 50 feet wide.

That’s no fault of the leads, who do what they can to enliven a screenplay with a one-note concept. Two kind-hearted souls who work in the same building are suddenly and callously dumped by their respective long-term partners. Emma (Slate), an orthodontic receptionist, and Peter (Day), a senior living facility board member, are both blindsided by their relationships coming to abrupt ends and their apparent soulmates quickly moving on to new lovers. While consoling each other in their shared work stairwell, Emma and Peter hatch a plan to try to break up the rebound romances of one another’s ex, paving their way for two reunions.

To do this, Peter begins working out at the gym where he takes Emma’s chiseled ex Noah (Scott Eastwood) as his personal trainer. Emma, meanwhile, volunteers on a grade school production of Little Shop of Horrors being directed by Logan (Manny Jacinto), the arrogant artist for whom Peter’s ex, fellow teacher Anne (Gina Rodriguez), has fallen.

Slate and Day wring as many chuckles as they can out of the screenplay by duo Isaac Aptaker and Elizabeth Berger (Love, Simon, “This Is Us”), but that isn’t nearly as many as you’d like. It doesn’t help that Eastwood and Rodriguez are both comedically flat, doing nothing to drive the plot we clearly know is a red herring all along. The script belabors every idea it has, as if Amazon insisted upon a minimum runtime. The movie draws out an impromptu post-clubbing hot tub party where Peter and Noah take drugs and learn the girls hitting on them are in their teens (a scene in which Pete Davidson cameos for no apparent reason). It does the same on an uncomfortable threesome that Emma has persuaded Logan and Anne to enter into with her.

The end result is that what should be a 91-minute piece of February fluff runs inexplicably close to two hours with only as many laughs as a somewhat promising 20-minute sitcom pilot episode might supply. The final half-hour is particularly brutal as Aptaker and Berger are determined to convince us we were wrong about where this is so obviously headed (we’re not). Day is never not entertaining and, though her body of work isn’t on his level, Slate’s chops are not too far behind. And yet they are given subpar material you expect to be given to fringe up-and-comers by novice screenwriters on a shoestring budget. The bar for February romcoms is set pretty low, so this is no disaster by genre standards. In fact, there’s a good chance it’s a lot easier to endure than the February romcom entrusted with standard wide theatrical release, Jennifer Lopez and Owen Wilson’s Marry Me. But it does nothing to benefit its likeable leads, apart from perhaps demonstrating that Slate is game to do musical theatre if necessary.