Mention the genre “romantic comedy,” and most moviegoers’ eyes roll with disdain. Say the words “sex comedy,” though, and eyes may widen with curiosity. Mix the two together with a bit of drama, and you might just get a perfect blend of sweet, spicy, and sharp. “Good Luck to You, Leo Grande,” available to stream on Hulu, comes close by combining all these elements to create an almost new category of film. The “Grande Dame,” if you will.

The premise is fairly straightforward: Emma Thompson plays Susan Robinson, a widowed, retired religious education instructor who hires the male prostitute “Leo Grande” (Daryl McCormack) in her effort to try out experiences that had eluded her as a married woman. During their first meeting, in an up-market hotel room, it becomes clear that Susan is traditional and repressed, but the movie’s tone is comic with nervous tension and even moving at times. An astonishing monologue delivered by Ms. Thompson concludes this initial meeting, and with what sounds like an organ playing softly on the non-diegetic soundtrack, it’s almost a religious moment.

During their second meeting, which includes the requisite romantic comedy dance sequence, things start to complicate as more of their personal beliefs are revealed. She pontificates about how young women wear inappropriate clothing that provokes male teachers and how young men need war to prove themselves, while he naively espouses on the utopian utility of sex work, how this “public service” can make the world a better place. If both of these chunks of dialogue come off a bit strained, they’re still rooted in the characters’ personalities, while also being well-written and -performed. 

The third meeting is where the drama enters the picture. Susan admits to Leo that she’s found out his real name and wishes to help him tell his unsuspecting mother about his vocation; Leo is indignant because the rules of their relatively impersonal encounters have been violated. This is the point where the movie’s resemblance to a play becomes more apparent and more unfortunate, for contrivances start to build up. The light-hearted yet heartfelt exploration of sexual awakening takes a backseat to labored explanations and arguments.

Thankfully, their fourth and final encounter, which begins in the hotel restaurant, wraps things up satisfactorily, with only a whiff of bad playwriting’s neatness. Kudos must go to screenwriter Katy Brand for her incisive script and skillful navigation of a “brief encounter” between an older woman and a young man. Director Sophie Hyde also deserves praise for taking a delicate two-hander and never failing to make it feel cinematic and lively. 

Ultimately though, this type of entertainment depends on its actors, and Ms. Thompson and Mr. McCormack deliver gloriously by seeming to really listen to each other and by reacting with tender, non-verbal cues. Mr. McCormack’s agent’s phone should be ringing incessantly after this portrayal, while Emma Thompson, one of moviedom’s great actresses, gives such a touching, gutsy performance that it will be remembered for years to come. “Grande Dame” indeed.