A genial anarchy has descended on the Royal Festival Hall as the audience readies itself to receive Anitta, Brazil’s biggest pop star. Born Larissa de Macedo Machado in the same year the Meltdown festival began, the 26-year-old is curator Nile Rodgers’ most eye-catching booking. The Chic guitarist has taken great care to ensure that his nine-day festival wraps its arms around as many ages, genders, sexualities and continents as it can, and Anitta embodies his inclusive ethos. A bisexual singer-songwriter-dancer-producer-manager brought up in the favelas and raised up by Instagram, Anitta has curated her career, her brand, to appeal to every possible demographic. Some, however, have criticised her for not denouncing the reactionary Brazilian president, Jair Bolsonaro, quickly or loudly enough, as if her very existence wasn’t a rebuke to his toxic stew of misogyny and homophobia.

The energy Anitta inspires tonight is hugely female, slightly gay and head-spinningly euphoric. There’s more Portuguese being spoken than English, and a bewildering number of you’re-not-going-out-like-that outfits for a Tuesday night, not least on Nile himself, who’s chosen a luminous yellow camo confusion that probably has a half-life of around 500 years. He’s an expert, self-deprecating crowdpleaser, lying on the stage for front-row selfies, then leading us in a thunderous chant of “Anitta! Anitta!” before diving out of the way lest he get crushed by the oncoming pop juggernaut. Everyone who can stand is jumping and yelling, and the venue totters on the verge of an actual meltdown.

Breaking into her 2019 crossover album Kisses, and its opening song Atención, Anitta doesn’t immediately have the best voice you’ve ever heard, but it’s strong and malleable, perfect for her music, a teetering tower of grinding, 15-certificate baile funk, reggaeton and modish urban pop-R&B that slows down only briefly, if at all. The stagecraft is, like her setlist, uncomplicated, efficient, calculated to create ludicrously exciting results. It’s focused around mostly female dancers in all-black outfits who spend a remarkable amount of their time on stage bent over, facing away from the audience, jiggling. Somehow it never seems sleazy, perhaps thanks to the ruthlessly professional, decisive choreography. It’s no ifs, all butts, the women in control. When one male dancer has to slap Anitta’s proffered bum, he does it sheepishly, looking pleadingly at the crowd as if he knows he’s being paid to do it, but still isn’t sure he won’t be sacked in the morning.

Anitta also slow-dances lasciviously with one of the female dancers, but mostly she crouches slightly as she sings, a hunter stalking the stage, setting out an unimpeachable string of hits as bait. The alpha and omega of her performance are the two long twerking interludes, when she sets the microphone aside and just goes for it. Within seconds, people in the aisles are imitating her moves, then freestyle dancing, singing and waving back at her. Later she does a mid-song slutdrop, sticks a tongue out at the nearest phone and breaks into a brilliant grin, all without breaking stride or dropping a note.

“We’re from Brazil, we like to shake our asses,” she declares with a knowing look, to a cacophonous reaction. “It’s 10% singing, 90% shaking my ass,” she lies. What this gig really adds up to is a bid for world domination. When a 26-year-old Madonna stares down balefully from 1984 on the giant video screen, Anitta’s lineage is made clear: a woman come to rule, certain of your immediate compliance. Sometimes a great gig is a surrender, the comforting feeling of fainting gently into a lover’s arms. Other times, specifically tonight, it’s like being kidnapped and held without ransom. During RIP, a girl in the crowd grabs Anitta’s arm as the singer stalks too close to the serried ranks of iPhones and just won’t let go – another hostage begging not to be let free.

Three days earlier, Chic’s opening ceremony gig is much more of a stately swoon by comparison. As ever with Rodgers’ fantastic band, there is an occasional frustration that a setlist entirely composed of some of the greatest songs ever sung celebrates their 7in rather than 12in forms: the true transcendence of I Want Your Love or Sister Sledge’s Lost in Music and He’s the Greatest Dancer is difficult, although not impossible, to locate in two minutes.

Although Rodgers’ fizzingly enthusiastic pre-gig opening address is fascinating, climaxing with a 15-minute explanation of how he rearranged David Bowie’s demo of a folk song called Let’s Dance into a worldwide disco-funk-pop smash, it’s hard not to imagine how some of this time could have been spent on a properly expansive Studio 54 Chic live set. Still, when you have an endless store of stories that begin: “So, one night David Bowie walks into my bedroom...”, you can do what you like with your time on stage.

Yes, it’s a shame that the festival is expensive and there aren’t more free live performances, which means it’s difficult for people to stumble across inspirational performers such as Anitta, or thrilling young Afrojazz collective Kokoroko, who bewitch the Queen Elizabeth Hall on Monday night. Still, the things Meltdown does well – smooth organisation, affable atmosphere and thoughtful curation – have been particularly notable in this 2019 edition. A great collaborator should make a great curator, and Rodgers is perhaps pop’s greatest collaborator. Importantly, his Meltdown is a love letter not to a type of music but a type of person, a call to the open-minded. Rodgers has long known that the key lessons of Saturday Night Fever, arts festivals such as Meltdown, and of disco itself, are that even those from the most closed communities can be transformed forever through music and dancing. His Meltdown is trying to tell us that sometimes just showing up is a political statement, that even hedonism can be a revolutionary act.