"This is that expensive rap," says Stormzy, half-way through the track Rachael's Little Brother. "It's coming like a dying art."
The lyric isn't a monetary reference, he's explained, but a metaphor for the sort of "classy, skilled, catching-all-the-pockets" lyricism he aspires to.
And yet… he's not afraid to loosen the purse strings when circumstances demand.
Take, for example, the star's first UK arena tour, which hit Newcastle on Tuesday night.
Put together by the team behind Beyoncé's historic Coachella performance, it's a lavish, no-corners-cut stage and light show that asserts Stormzy's status as the country's biggest rapper.
This is the sort of show that makes room for pyrotechnics in almost every song; alongside a 12-piece band, a two-pronged catwalk, five budget-busting video screens and - symbolism ahoy - a serpentine lighting rig that twists into the shape of a crown.
But for all that spectacle, the main focus is the man born Michael Owuo Jr - from the moment he emerges on a swaying platform, high above the arena floor; to the closing bars of Vossi Bop, where his vocals are drowned out by 11,000 phone-wielding fans.
He opens the show with a trio of his fiercest songs - Big Michael, Audacity and Know Me From - high-stepping through fireworks as he whips the crowd into a frenzy.
For the first half an hour, he's the only person on the stage, his charismatic swagger the show's sole source of energy (if it could be bottled, it could presumably solve the fuel crisis).
Acknowledging that all eyes are on him, the ultra HD video screens emphasise his lyrics - especially on the punchy First Things First, which tackles everything from depression to institutional racism, via the demonisation of UK rap and his love of Adele.
After six songs, Stormzy switches up the pace with a stirring gospel-soul section that introduces a full live band, featuring no less than six backing singers.
They lead us through the star's more contemplative songs (Crown, Superheroes, Do Better) while adding a late-night urgency to the sensually-charged Cigarettes & Cush. As the tempo slows, the star lets out his playful side, flirting with the crowd and busting out some surprisingly supple dance moves.
"We're going to create some memories tonight," he declares. "I want everyone to leave here with a little bit of joy in their heart."
To be brutally honest, the slow-groove soul revue outstays its welcome by at least two songs - and it's a relief when Stormzy ratchets the energy back up with the ferociously articulated Wiley Flow (the line "I can't drop the bag, I am the bag," remains a highlight of his discography).
The pace doesn't falter after that, as the star races through his biggest hits - Clash, Big For Your Boots, Blinded By Your Grace, Shut Up and Vossi Bop.
Some of these are performed inside a giant, oscillating scale of justice (which, like the metaphor, went completely over my head). Others are delivered, to maximum audience approval, while wearing a Newcastle United t-shirt that's been thrown onstage.
Throughout the show, Stormzy is in jubilant form, turning the Utilita Arena into a giant shoobz, or all-out grime party. For many in the audience, it was their first concert since the Covid lockdowns - a fact that wasn't lost on the star.
"A lot of you bought a ticket two years ago, so to see you here today is a real thing," he said.
"The past two years for me… I've done a lot of growing as a man and I've been making music, and I've been chilling, and I've been spending time with my family, and I've been so away from everything.
"So even driving to the arena and seeing everybody waiting outside, I was like, 'We're still here man, we're still alive.' I love you guys."
And for all the expense and all of the spectacle, that's what endears Stormzy to his fans: The humanity of his music and his actions.
That's why the best moment of this, the first full show of his 2022 tour, came after the music finished and the house lights went up.
Instead of being whisked away to a velvet-roped VIP area, Stormzy climbed off the stage and spent time with the people who'd waited two years to see him.
The crowd frequently threatened to swallow him whole - but he was undeterred, shaking hands and posing for selfies for as long as time would allow.
It was a personal gesture of gratitude; a sign that, for all of his stature, Stormzy knows where his power comes from.
And he repaid that debt by announcing his forthcoming third album to them first - not on social media, or in an exclusive interview with Rolling Stone, but in a video played exclusively to the fans in the arena.
This is that expensive rap, and it's coming like a dying art.
The Heavy Is The Head Tour continues through March and April with dates in Leeds, Sheffield, Manchester, Liverpool, London and more.