Spend any time talking with those in the documentary sector, and they’ll lament how hard it is to land commissions without having a celebrity aboard – a precondition that invariably impacts on journalistic rigour.

If you’re seeking the greenlight for a magazine show on 21st century sexuality, however, attaching model-turned-actor Cara Delevingne, polysexual pin-up and three-time Eyebrows of the Year winner, isn’t the worst idea. The pros and cons of “Planet Sex,” a new six-part Hulu/BBC co-production (Hulu’s version will air in 2023 as Americans will get a different version of the show that’s still being edited), are tied up with Delevingne’s game, anything-goes persona, here recruited in a bid to distract 18-to-25-year-olds from Tinder-pounding. As Cara puts it early on: “Let’s get the 101 on the power packed in our pants.” Anyone cringing should know: a) you’re likely outside the target audience, and b) it gets better.

At the very least, “Planet” arrives as a marker of how sex education has changed over the years. Updating the patrician public information films and clinical school programming of yore – insinuating sex was best conducted under laboratory conditions – here is TV that is chatty and casual, closer in tone to a dorm-room heart-to-heart. There’s also been a clear shift in what’s being talked about. The stance this globetrotting overview adopts is female-fronted and -focused; redirected from penetration and procreation towards more mutually advantageous, pleasure-centred activity; big on the C-word (consent); and keen to explore the full rainbow spectrum of human sexuality. It’s moist with positivity: this may be the first show in small-screen history to feature both the BBC logo and the phrase “a nice big squirt.”

That said, even Delevingne has had her work cut out loosening up a show bound for BBC3 primetime. “Planet” emerges from the shadow of Channel 4’s much-exported “Naked Attraction,” which bolstered its giggly, bits-out gameshow with self-justifying factoids, and a run of late-night cable shows, headed by HBO’s long-running “Real Sex,” which enjoyed far greater leeway in illustrating what its subjects were, you know, doing. Cara racks up airmiles and outré erotic encounters: attending women-only orgies in New York, sex labs in the Netherlands (naturally), and a vagina art workshop in Tokyo. But broadcasting restrictions ensure there’s often more tell than show. An episode on porn and its effects largely raids 1950s B-movies for its imagery; a masturbation experiment cues nudging stock shots of oysters and beavers.

Delevingne, in other words, is here to see and do everything the viewer can’t. To her credit, she’s a sparky, funny, natural presence, joshing “this is like my house” upon entering a sex therapist’s mask-and-paddle-filled loft. (In the series’ most relatable moment, she stumbles over her own surname while checking into a hotel hosting the world’s biggest lesbian pool party: “It’s hard to spell.”) Still, there is a lot of Cara here – pulling faces, goofing off, walking into trees. Her to-camera addresses – on her own habits and hang-ups – are admirably candid; there’s scant trace of filter here. But in the show’s weaker stretches, she can’t help but resemble a very posh girl galloping through an especially horny gap year. Those who don’t find her millennial restlessness stimulating might well find it grating, or – worse – a total turn-off.

That would be a pity, as there are segments of interest in every instalment, whatever your leanings, however you identify. (Any aspirant swain failing to locate the clitoris after episode one – on the so-called “Orgasm Gap” – can safely be dismissed as a hopeless case.) The porn episode initiates a mature, multifaceted conversation on a topic non-cable television has generally approached with (at best) sniggering embarrassment, while episode four brings first-person clarity to society’s current confusion around gender. Here, “Planet Sex” moves beyond wide-eyed-and-breathless travelogue filler and transcends its initial kookiness. For one, it’s an eyeopener to learn that even our gabby, liberated, unabashedly queer host envies the freedoms enjoyed by those coming out in her wake. Turbocharged online, sex itself has changed – has evolved – so quickly everyone’s scrabbling to stay in touch.
Seasoned satyrs may just raise an eyebrow and return to the boudoir, missing – say – the Japanese woman getting hitched to a (wholly pixelated) character from “The Sims 4.”

Yet as pitched towards a demographic of young adults, “Planet Sex” comes to seem faintly radical: as questing and curious as the science it regularly rubs up against, open to new experiences and new information alike. Previous packages of this ilk would likely have sneered at Mrs. Sim; here, she’s framed altogether sympathetically, as one of many confused souls yearning to escape or reinvent the heteronormative template.

After overseeing an Erika Lust porn shoot, Delevingne signs off in a way that pinpoints the intimacy “Planet Sex” seeks to foster, and the fears it means to banish: “It wasn’t that strange. Sex is way more scary.”

“Planet Sex with Cara Delevingne” debuted on BBC3 on Dec. 1. All six episodes screened for review.

Executive producers: Cara Delevingne, Simon Andreae, Fiona Caldwell, Katharine Dart.
Producers: Olivia Strong, Rachael Getzels, Cara Warwick, Ayanda Duma, Camila Mejia Calle.
Line producer: Venita Singh-Warner.