A splash of Evian from a polystyrene cup seems to suffice on this occasion, and Omar's live performance for VH1's Take It to the Bridge gets under way. "Little Boy" features the kind of treacle-rich vocal glissandi guaranteed to keep those Stevie Wonder analogies coming, but as Omar's new single "Golden Brown" testifies, you categorise him at your peril.
Here at MTV, the song is stripped to a bare-bones arrangement of acoustic- bass and vocal. On the This Is Not a Love Song album, however, Omar's beautifully orchestrated reading of the old Stranglers hit has a swinging feel and a minor-to-major cadence that betrays his classical roots. Fine and dandy then. But a soul artist covering the Stranglers? Surely some mistake?
"Well, no, because I always thought it was a magical song, and I didn't want to just dip into the R&B back-catalogue like a lot of people do," he begins. "The other thing with `Golden Brown' was that The Stranglers were supposed to be a punk band and there they were doing something which transcended the genre.
"I remember spending pocket-money on that, the Police's `Regatta De Blanc', and Earth Wind & Fire's `Let's Groove' when I was about 11. At the time I didn't realise `Golden Brown' was about heroin, of course. I thought it was about a girl, like `Brown Sugar' by D'Angelo."
It soon becomes apparent that this "transcending genres" business is a key issue for Omar. He's often lauded as a "nu classic soul" pioneer - "classic" signifying a certain emphasis on musicianship over technology, and a preference for organic sounds rather than, say, samples or loops.
But it's only half the story, and he's not fully comfortable with the tag. "To me, `nu classic soul' is just `acid-jazz', and in five years' time it will be called something else," Omar explains. "I think that the music business in general is obsessed with labels and categories, whereas my philosophy has always been that music is just music. People should be able to listen to Holst, then move on to Nirvana, then move on to Bill Withers."
At this point, he pauses for a second, leans forward, and the heavy silver- chain around his muscular neck rattles a little. "I do think that it is important to listen to the pinnacles in each genre, though. You don't want the Mercedes 190, you want the 600... do you know what I mean?"
Though here in Britain Omar is still best remembered for the sweet summer groove of his 1990 single "Nothing Like This", in America his name is currently the one to drop.
Major-league contemporaries such as D'Angelo, Erykah Badu and Maxwell all sing his praises in interviews, and he recently wrote and produced a number of tracks for Epic Records' new soul starlet, Laurnea.
"That was a strange sequence of events actually," he smiles. "I was at my first LA party and there were all these famous faces: Snoop Doggy Dogg... whoever. I thought I was the stranger in town and then this girl (Laurnea) came up to me and said, `Hi! I know your mum.' What I didn't know was that she'd lived in London for a bit when she sang with Soul II Soul. It turned out that she used to go to the same gym as my mum. We became friends after that."
If the name-checks from his peers are flattering, then the fact that Stevie Wonder (to whom Omar refers simply as "the Don") is also a fan is an honour.
Though Wonder has promised to write Omar his first No 1, the pair have yet to record together. They have duetted on French television, however: "I was totally shit-scared, and we sang `Don't You Worry 'bout a Thing'," he remembers.
"I must have sang that song a thousand times, but when the Don was in the room, I still needed the lyric sheet."
It's clear that Omar felt a similar sense of reverence when Syreeta Wright - Stevie Wonder's ex-wife - came down to the This Is Not a Love Song sessions to record "Lullaby", a duet he had written especially for her.
Omar explains how he had tailored the track's sound to complement Wright's voice, and confesses that when it was time for him to record, he had been so moved by her performance that he couldn't sing.
But was it taboo to talk about Stevie with Syreeta? "No, not really," he says, fiddling with the silver hoop that pierces his left eyebrow. "She'll speak fondly of him, but then you know it is inappropriate to probe further.
"It's the same with Stevie, actually. A while back me, Galliano and a couple of other guys had the chance to interview him for an electronic press-kit package that was being sent out to promote his Conversation Peace album. Syreeta has the most beautiful speaking voice too, and I asked him if that was what made him want to marry her.
"He said that he still loved her dearly as a person, but he didn't really answer my question. He has done so many interviews now that he is on auto- pilot."
Back on the set of Take It to the Bridge, Omar is about to close with some "percappella" - a kind of a cappella performance in which the body is used like a percussion instrument.
He's having a bit of trouble with some trapped phlegm, so the floor manager brings over his Evian. "Excuse me!" Omar calls after her in mock-regency tones. "Do you think that I could have this in a crystal glass?"
"Seventeenth-century OK?" she responds, completely dead-pan."Touche!"
`This Is Not a Love Song' is available now on RCA Records. Omar Lye Fook's version of `Golden Brown' is out on 6 October