On a scorching afternoon at the Young African Art Market, an open-air Berlin bar more commonly known as YAAM, two children of the diaspora, having met for the first time, sipped half-yards of beer and engaged in a common routine: the cultural compare and contrast. For this Australian-Ugandan, the British-Nigerian artist who identifies herself only as Klein explained her people's reputation as a particular type of scene-stealer. "The Nigerian diaspora is the most gassed," she said. "We are the loudest. Like, if there was a room filled with two Nigerians, five Ugandans, ten Congolese and three Jamaicans, why are you hearing the Nigerians the most? Two minutes in there we would have made a Nigerian flyer. Nigerians are like, 'Everyone is gonna know that your grandad is the chief of the village, and that you're actually a princess AND you're gonna be fleeky too."

To borrow from the headline of the interview she did with FADER last year, "Klein is funny as hell." The South London composer, singer and sound collagist is also one of the most intriguing figures in electronic music right now. In song, onstage and in conversation, she has a ready supply of un-ironic jokes, a rapid-fire magazine of pop culture references and a sense of unyielding forward motion. The most-used term in her vocabulary is "spiral," which she deploys as both verb and adjective. Anyone more than a half-step behind her knowledge of 20-something London slang will be left in the dust.

Then there's that voice. When Klein permits it to appear without her glitchy pulses, pitch-bending and left-turn transformations, it is revealed as a rich and honeyed contralto, nimbly flitting up or downscale and across many reference points of black vocal traditions. The landscapes of Klein's sound world are all there in "Prologue," the opening track of her 2017 EP Tommy, released on Hyperdub. A heavy-handed piano melody snaps off into silence, a solitary Klein trills a sweet Toni Braxton vocal, but breaks up into laughter. She's joined by bantering friends, makes a joke about just doing ten-minute Mariah Carey-style vocal runs, and then the song collapses outwards. It becomes a living, growing fractal of voice exercises and woozy multi-tracked notes, all before the music is introduced, which progresses in swerves and shifts.

Tommy was named after a cast-member of the Atlanta franchise of the reality show Love & Hip Hop. Klein considers her follow-up from May, CC, to be her most personally revealing work yet. "I wanted to make a record that I knew was 100% me," she said. "If you like it, that's cool, if you don't get it, that's fine, but at least I put it out in the world. The title came from when you cc someone on email to let them know what's happening. Those seven songs lets whoever into my music, like, 'This is who this girl is. This is her best friend, this is her cousin, this is where she grew up, this is the boy she doesn't like.' That's why I call it a coming of age record."

"Coming of age" is a phrase that points to the benchmarks of young adult development, and hints at the rites of passage that were necessary to get there, so it seems fitting that CC is a trip of both dreamy and nightmarish qualities. "Collect" features saccharine fairytale strings and the spoken-word recollections of Klein's friend, Diamond Stingily, the American artist and poet, and daughter of iconic house vocalist Byron, who talks about a childhood preoccupation with death and the adult pains of earthbound bodies. At the EP's midpoint is "Born," a skeletal 4/4 track constructed mainly of glitchy static and unsettling drones, accompanied only by occasional weeping and what sounds like a gun being cocked.

"I wanted to make a track that sounded like it could be played at a techno club," she said, "but I wanted it to communicate the feeling of, like, having a teenage meltdown in a club environment... [CC] spiraled into me delving into relationships within myself or relationships with certain people. 'Apologize' is me upset, like, 'I'm out. I won't do this again.' Then when the beat comes in it's almost uplifting. Actually the most uplifting is the most spirally song, 'Ex Play.' It sounds like a carousel [and I'm] like, 'I just want to cry, man, I just want to die.' I found notes in my phone of me being like, 'I hate everything,' and I was like, 'Imagine if I repeated that, and just manifested it.' So, 'Ex Play' is very much about depression and trying to deal with that, but in the same breath being like, 'I don't give a damn, because I'm lit!' It's the happiest carousel beat I've ever made. It's just so dumb, because you hear the song and you, like, want to twerk."

A few weeks after the release of CC, Klein announced she had been invited to support Björk on two July dates of her tour: the first at the Rainforest Biome at the Eden Project in Cornwall, England, and then Gent Jazz Festival in Belgium. The two artists had initially met outside the entrance of London venue Corsica Studios, then again after the Icelandic star saw Klein's performance at Sónar Reykjavik in March.

"After that she sent me an email saying, 'Hey, do you want to play with me?' I was like, 'Cool.' Everyone else was freaking out, but her music sounds like a Disney fairy angel, and I'm the same, but the darker side. I feel like the Ja'far to her Anastasia. But it wasn't until the day of the show that I was like, 'Wait a minute. I'm freaking out!' I used to listen to Björk's music when I was a kid, it's crazy that I can just text her for banter."

I'd met with Klein on the day of her performance at A L'arme Festival in Berlin. She'd last played in the city for CTM Festival, where she'd delivered a meditative and introspective performance at Berghain. Positioned across the floor from the usual stage, she perched by the railing above the club's imposing Dionysus statue. "If I fell back I would fall all the way to the ground," she said. "I was like, 'Berghain is trying to kill me.'" There, bathed in hues of red, the audience closed in for a solemn work of live vocal sound-collaging. As it turns out, that raw, intense performance came from her being overworked and ill; Klein had flown to Berlin in the middle of an intense writing and rehearsal period for Care, the live action musical set in a youth care home that she'd written, scored and starred in for London's Institute of Contemporary Arts. "My acting was very Michael Cera, very Juno," she said. "I was like, be grateful that you make decent music."

Where the CTM show was meditative and focused, the sweltering discomfort of A L'arme's venue proved the perfect stage for an hour of outré, extroverted Klein-ness. A live violin and cello duo opened the performance on stage left, then Klein appeared stage right in a Madonna-style headset, backlit and engulfed in smoke. Looped videos showed black and brown bodies engaged in movement and dance. Then, one of these figures, her frequent performance collaborator Josiane Pozi, appeared in real life, for a solo dance piece and a pose-off mirror dance with Klein to "Explay."

"I was so turnt," Klein said a few weeks later about the performance. "[Otherwise] that would have never happened. You would have not had any You Got Served moments."

The most stunning moment of her A L'arme performance came after the string players left the stage and before the dance-off. Klein improvised a harmony against a synthesised choir created of her own natural instrument, and unresolved piano phrases melancholic enough to break a heart. It was a soulfully weird moment, experimental with wide open doors of accessibility, beyond the legacy of gospel or the bed of avant-garde production. Klein's performance spoke to the deepest midnight blues. When I mentioned this, she cited an admiration for American avant-blues music and the visual artist Willis Earl Beal. "I really like the fact that he's able to fuse old school with a modern sensibility," she said. "It's not a conscious effort, but eventually all your influences sort of come together."

The kinship doesn't end there. Press coverage of Beal routinely mentions his bristling against the assumptions drawn about his identity as an African American man and musician. Klein talks about her experience as a black artist in experimental music, with "weird situations" taken directly from the racialised play book of individual exceptionalism.

"When there are people that look like me that make this music, and kind of just use their brain [to do it], whether it's me or Chino Amobi or whatever, it's like there has to be a reason for us to be there," she said. "Like [we] had to have been through some traumatic thing. But it's like, 'Actually, no. I'm just an airhead who can barely use a washing machine, but I just happen to be able to make this.' I see a lot of that kind of thing whenever I come across stuff that's written about me or friends of mine who make really cool music. It's like with Usain Bolt, people are like, 'His bones must be stronger!' I'm like, 'nah, he just runs faster.'"

Klein's new material takes a more straightforward approach to her beloved sounds of pop and R&B, with less vocal obfuscation. "For me, making music is what's always at the forefront," she said. "Anything else is secondary. There's a part of me that's shy about my voice."

As a sound reference for what may come, she mentioned her own 2016 track "Gaz City," from Only, with its stark piano chords, dusky vocal runs and minimalist electronic soul. I made a tentative comparison between the sound of Only and pre-superstar era James Blake. Klein was audibly, hysterically gassed at the thought of riding a similar arc to pop recognition. "Imagine if I stepped into that world," she laughed. "It's a wrap. At the VMAs. Doing a song with Shawn Mendes! It would just be like the early 2000s all over again. You know, when pop music used to be weird."