'Red, White & Royal Blue' gives the US-UK relationship a rom-com ...

What’s diplomatically known as the US and UK’s “special relationship” takes on a different meaning in “Red, White & Royal Blue,” a light-on-comedy modern romance in which a British prince and US president’s son passionately fall for each other. Aspirational in its progressive politics, the Amazon movie is a polished and unforced adaptation of Casey McQuiston’s bestselling novel that wears its heart on its red, white and (royal) blue sleeve.

Playwright Matthew López makes his directing debut with the film, which filters issues of coming out to one’s family through the prism of two of the most under-the-microscope families on the planet.

Getting to that, though, requires overcoming a somewhat clunky start, as Britain’s Prince Henry (Nicholas Galitzine, also a prince in Amazon’s musical version of “Cinderella”) – second in line to the throne, a.k.a. “the spare” – and presidential scion Alex Claremont-Diaz (“The Kissing Booth’s” Taylor Zakhar Perez) dislike each other when they’re thrown together at an international soiree, which ends in an enormous sight gag.

The incident prompts Alex’s POTUS mother (Uma Thurman), who is in the midst of a tough reelection campaign, to push her son to conspicuously mend fences with the Brits by appearing with Henry, only for both to be shocked when what begins as a friendship and a lot of long-distance text messages takes a decidedly romantic turn.

As complications go, few match those that the prince faces, inasmuch as the life of a Royal is essentially built around being displayed as an object of public curiosity. Yet Alex has his own issues, including his desire to be taken seriously as a contributor to his mom’s campaign, despite the skepticism of her aide (Sarah Shahi), who, like most others, just sees him as a handsome party boy.

Beyond the steam emanating from the relationship between the dreamy Alex and Henry – fueled in part by the clandestine nature of their encounters, which involve an Olympic-caliber degree of difficulty – “Red, White & Royal Blue” is perhaps most notable for its uplifting view of US politics. Apparently eager to imbue that with some street cred, the filmmakers enlist MSNBC anchors Rachel Maddow and Joy Reid, who each garner fairly extensive screen time as themselves.

Like many screen romances, the attraction is only as good as the impediments thrown at the couple, and in this case, those are a doozy. As Henry notes, having grown up hiding who he really is, the thought of entering the spotlight through the lens of politics would basically force him to “trade one prison for another.”

In that respect, as well as its handling of sex, the movie is a bit more adult than most YA titles; otherwise, “Red, White & Royal Blue” is at its core a fairy-tale romance – only where the challenge isn’t the customary wicked stepmother or malevolent witch, but rather what happens when true love finds two princes, not one.

“Red, White & Royal Blue” premieres August 11 on Amazon’s Prime Video. It’s rated R.