Stars prepare for 'celebratory' David Bowie Prom
A little over 10 years ago, in May 2006, David Bowie gave his last ever UK performance at London's Royal Albert Hall.
He only graced the stage for 15 minutes, as the special guest of David Gilmour, singing the Pink Floyd classics Arnold Layne and Comfortably Numb.
Now, six months after his death, the star's own music will finally be heard at the iconic venue, as part of the BBC Proms.
Curated, conducted and directed by Andre de Ridder, the concert will span Bowie's entire career from Space Oddity to Blackstar - the "parting gift" he gave his fans in January.
"I just have to keep my wits together," laughs the Berlin-born musician as he oversees the final rehearsals at the BBC's Maida Vale studios.
As we arrive, de Ridder is putting the Stargaze orchestra through their paces on Fame, the angular funk track Bowie wrote with John Lennon in 1975.
"It sounds beautiful but it sounds a little classical," he decides, instructing the musicians to start again.
They dutifully leaf back through their score and break into the song's needling guitar riff - here transposed to flute and clarinet.
"Always stay on the groove," de Ridder reminds, before asking the brass to add "a little bit of growly stuff" to the bottom end.
Sitting quietly in the middle of the semi-circle is singer Laura Mvula, the mic stand clasped between her legs as she awaits her cue.
The song builds, she grabs the microphone and leans into the beat. "Is it any wonder, I reject you first?" growls the star, her head bobbing.
Over the next 15 minutes, the song slowly comes into focus, before the orchestra breaks for tea.
"For me, this is like a masterclass," says Mvula, who will perform three songs on Friday night. "I feel like I'm feasting on really important music.
"I would consider Mr Bowie alongside Prince and alongside Stevie Wonder. To me, it's a deeper reverence than fandom. The lasting effect of what he's done is eternal. It's beyond classic music. I'm very privileged even to be in the room."
As befits the Proms, the songs have shed their original form, with gospel choirs, double basses and kettle drums now drawing out undiscovered detail in Bowie's compositions.
"His songs stand the test of time but also the test of many different metamorphoses," says de Ridder.
"In the process of making the arrangements we found, for example, that a lot of the songs that have a very strong beat in the originals don't necessarily need that. Harmonically and melodically they have so much intricacy that maybe, in some of these arrangements, is brought out a little bit more.
"We really tried to bring in a great variety of composers and singers and interpreters from different genres and styles."
Chief among them is John Cale, the former Velvet Underground star and musical iconoclast, who not only collaborated with Bowie - he taught him to play the viola.
"He was always very inquisitive. A very creative person," making, he says, the sudden finality of his death all the more shocking.
"It still guts you when you think about it."
Cale is performing Valentine's Day, Sorrow and Space Oddity. In tribute to his friend, he is treating the work with zero reverence.
"Space Oddity - I push it in a different direction," he says. "I put in a trance beat. I've added a really great street gospel choir and we share the vocals.
"The people that are coming to this, they're not just coming for David Bowie, they're coming for David Bowie-plus. And they're not going to find it wanting."
The rehearsals at Maida Vale's Studio 3 (where Bowie once played an exclusive concert for Radio 2) run late into the night.
Artists including Neil Hannon, Conor O'Brien and French counter-tenor Philippe Jaroussky drop in to run through their performances, ahead of Friday's dress rehearsal at the Royal Albert Hall.
It's slightly shambolic, as the Stargaze musicians flick back and forth through the programme, to accommodate the schedules of their guest stars.
Amid one flurry of sheet music, de Ridder jokes: "This is the nightmare part we want to avoid tomorrow night - where we can't find the scores."
But the conductor generates a sense of calm that permeates the room, no matter how fraught he might be feeling.
"I'm a little bit scared about getting to the night and looking into people's faces in a sold-out Albert Hall," he confesses. "About what the reaction might be and how we might be overwhelmed ourselves.
"But as performers, this is always the challenge, to focus on what we've practised and let the emotions come through, to a certain extent."
The singers are much more sanguine.
"It'll be celebratory and exciting," says Cale.
"I think it will be special - not just for David's fans, but for music lovers," adds Mvula.
"It's going to be a really important night."
The David Bowie Prom will be broadcast live on BBC Four, Radio 3 and 6 Music at 22:15 on Friday, 29 July.