It's Thursday July 3, and tomorrow the American singer-songwriter who goes by the single appellation Pharrell will appear second on the bill of the Wireless festival in Finsbury Park, north London. But for now, he's the star attraction at a fourth of July party at the London residence of the US Ambassador to the UK, Matthew Barzun.
The handsome hitmaker, responsible for the three biggest global smashes of the past 18 months - Happy, the equally ubiquitous Get Lucky by Daft Punk, and Robin Thicke's Blurred Lines - brings a big-hatted fashion glamour to any party. And right now, he can do no wrong.
Take Happy, for instance. Starting life as a song on a cartoon soundtrack (Despicable Me 2), the spirit-lifting anthem to exuberance reached number one in Ireland, the UK and the US, and has had 350m YouTube views. It has become more of a movement than a song, with (at last count) more than 800 fan-made versions of the video produced worldwide.
In July, six Tehrani youngsters who filmed themselves dancing to the song on rooftops were arrested by the Iranian regime, accused of producing a "vulgar clip which hurt public chastity". Presented with evidence of the outpouring of global love for the track by Oprah Winfrey, the normally ice-chilled Pharrell was reduced to tears. Even his sky-scraping Buffalo hat, a re-imagining of a 1982 Vivienne Westwood design, and initially ridiculed as a fashion stroke too far after he premiered it at January's Grammy Awards, is now acceptable (although perhaps not on anybody else).
Williams has been this way - a relentless blur of ideas, contacts, collaborations and style - since growing up in Virginia, the son of a school-teacher mother and house-painter father. He says his parents never doubted his abilities as a teenage producer or the viability of a career in music. "I didn't go to college 'cause right out of high school I started music, so I was making more money than they could explain. They didn't understand it at first, but they were very supportive."
At Wireless, the now Miami-based jet-setter is appearing just below headliner Kanye West, with whom Pharrell once had plans to launch a fashion line called Pastelle, before both decided to concentrate on individual fashion lines. On T In The Park's main stage he was next to Ed Sheeran, whose number one single Sing was written with Pharrell.
When I recently interviewed the British singer-songwriter, Sheeran explained that it was Pharrell who helped persuade him to release the game-changing song as his second album's first single.
"I wasn't trying to say it in a cocky way," Pharrell clarifies, before embarking on a bout of speechifying that is part Zen master, part motivational speaker. "Like, I don't need the money or I don't need the hit . . . I was saying to him, 'Our sessions were good in a way that I felt like they were very holistic for you. Because you let go of what was comfortable to you, and discovered a new part of your personality.' One must let go in order to see who they are. When you're clamping down, and your talons . . . if you will . . . are clenched into your nest, then you will never experience flight. And when Ed let go, a whole new part of him came out."
This evening, Pharrell too has unclenched his talons. The ambassador's home in Regent's Park boasts the largest private garden in London after Buckingham Palace, and outside it tonight is what must be the longest queue in Europe. The line of finely attired guests awaiting entrance to Winfield House stretches for hundreds (and hundreds) of yards down Regent's Park's Outer Circle. Luckily, if you're with Pharrell, you get to bypass hundreds of beautiful people and skip to the front.
And he's not even performing. Rather, he's here to look over Maxine Ashley, a young New Yorker who Pharrell, in partnership with British songwriter Amanda Ghost, has signed to his new record label. Tonight, on the ambassador's lawn, Ashley is singing The Star-Spangled Banner.
Pharrell makes his way down the finely manicured slope like a celebrity snowplough, a path clearing before him then bunching up behind as the great and the good clamour to touch the brim of his cloud-busting hat. But Pharrell is not for turning. As soon as Ashley steps off the stage, he takes her by the elbow and leads her away from the crowd. He stands amid the (as-yet-unlit) fourth of July fireworks and offers his new charge some performance tips.
Meanwhile, the ambassador's guests hover, excited, camera phones out, poised for selfies. The most talked about man in music is here, and - with or without him singing - America's biggest holiday feels like a party.
It's very different from the Pharrell I meet in a central London hotel a few weeks earlier, while he is on a brief visit to the UK. He steps out of the lift like he's just stepped out of a salon run by [1970s cartoon character] Mr Benn: big hat, big sunglasses, massive amount of bangles, chains and gewgaws.
"This appears to be a woven hat but it's really carbon fibre," he says proudly of his bespoke Adidas titfer. "Too expensive to put out . . . And these are real freshwater pearls," he jangles, "and this is real gold. But unpolished, so it doesn't shine. So it all looks fake. But it's real."
This singer, songwriter and producer has a lot going on, and not just in terms of his outre style. Is that busy-ness a product of the synaesthesia from which he reportedly suffers? (The neurological condition causes a 'blending' of the senses, so sounds manifest as colours, or letters as smells).
"It's not suffering," he replies, quietly, slowly. "It's just the way I've always seen music. But there are so many people who are like that. It's not a rarity. One of the main things I try to educate the public on is, most artists have it."
Pharrell has long been a very in-demand artist-producer. Among myriad other achievements, he co-produced and co-wrote many of the songs on Justin Timberlake's huge-selling first solo album, Justified - songs that he and his producing partner, Chad Hugo, (they call themselves the Neptunes) wrote with Michael Jackson in mind.
But over the past year or so, Pharrell's profile as a falsetto-voiced star has gone stellar. His second solo album G I R L is selling like hot cakes. Even if "most artists" have synaesthesia, not many can turn it into musical gold the way Pharrell can.
How did he visualise Happy, Get Lucky and Blurred Lines, songs he co-wrote and sang? "It's more of a colour thing," says Pharrell.
OK. What colours would he describe them as?
There is a pause. A very long pause. Get Lucky, he eventually begins, is "more like Renaissance-type colours. And Happy is like yellows. And mustards. And slight slivers of orange and a tinge of brown in the verses. And in the choruses, it's more like sherbet colours. Like bright sherbet orange. Like pastel oranges. And blues. It's very rainbow-ish. Because those are like minor colours. But they're exotic colours, juxtaposed to the sharpness and the brightness of the major sensation that's in the verses."
"That makes sense," I flounder. I can't tell if he's taking the mickey out of me, or being sincere. Not being able to see his eyes or read his expressionless face isn't helping.
Yet Williams is super polite. When he spots a beseeching note from my 12-year-old daughter among my questions - "get Pharrell autograph. PLEASE DON'T 4GET" - at first he apologises for looking, then breaks into a big smile and says, "anything she wants, no problem". But at the same time, he's already radiating sleepy, not-quite-there vibes, which is more of a piece with the Pharrell I remember.
I've met him twice before, the first time in 2004. He and Hugo's performing alter-egos Nerd were supporting the Black Eyed Peas on tour in America. After much international schedule-juggling and lengthy delays, I sat down with Pharrell in the windowless basement staff room of a Tower Records store in Philadelphia. By that time, neither of us much wanted to be there.
The last time was in 2007, in a fashion company's office near Shoreditch, east London. Pharrell was in town for the pan-European launch of his clothing labels Billionaire Boys Club and Ice Cream. Again, we didn't exactly connect. He was more interested in his BlackBerry.
Talking to him now, I broach the subject of his conduct - rude, frankly - in the past. He wasn't very good at interviews, I begin. He nods.
"But I was appreciative that everyone was patient with me. I was happy with everyone being so patient with my misunderstanding of what promotion was for and why it was necessary."
Having confessed, the meandering-but-at-the-same-time-loquacious Pharrell embarks on an explanation, thanking those who were "generous enough to see the brighter side of my personality and the brighter side of my intentions" despite his "ignorance".
There is, indeed, a sense that Pharrell has learnt his lesson. As well he might. After a stellar early 21st Century, Pharrell went off the boil around the time of his poorly received first solo album, 2006's In My Mind. He admits as much when we discuss the topic of his 2013 marriage to model/designer Helen Lasichanh (they have a son, born in 2008. He's called Rocket). Prior to their relationship, he had a long stint playing the field and, as a musician, was hardly known as a beacon of feminism.
The notional concept behind (and the name of) G I R L is part of his rebrand, something that was even more necessary in light of Blurred Lines' lyrics - described by some as "rapey", and which contributed to the song being banned in a number of British student unions. He says his album's title has that typographical look because "I wanted it to read differently in text. 'Cause there's so much between those letters. You know?"
I don't, so I let him press on. "I wanted to give back to a demographic that has just been giving to me for over 20 years, which is women. I have male fans, too," he confirms. "But the women, they never left my side," he says, which is no doubt true. "I wanted to explain my affinity for them from A to Z."
Pharrell is not happy about gender injustice and inequality, from wages to human rights. "Certain places on Earth, there's still legislation that tries to tell women what they can and can't do with their bodies. Those things need to change, and need to change rapidly.
"Because the perception is that we live in a male-dominated society but we really don't." Well, we do, but Pharrell is talking in biological terms.
"The real truth of the matter is that no human being can be created without going through the conduit of a woman's body. Men don't make eggs. We contribute to them. Nor can we give birth. So woman are at the centre of humanity, and they need to be treated as such," he concludes firmly. On both a personal level, then, and a political one - he is very much a Hillary man for 2016 - Pharrell credits women with turning things around.
"I think I got married because I looked at life much differently after . . . feeling like . . ." He stops and gathers his thoughts from somewhere. "The end of '07, I felt like I had no purpose." A big pause. "I was more concerned with the imagery the music stimulated versus the music itself."
So his last solo album suffered?
"Yeah, because there was no real intention for like - I'd say 80pc of it was braggadocio," he admits. "Most of it was just like, I wanted to compete with my peers.
"But this album," he says of his oddly titled, yellow-hued project, "was all intention, all purpose. That's why I'm ever so grateful. Because it's just been met with a warm reception.
"I'm often asked, 'Why do you think it's turned out this way?' And I'm happy that I don't know the answer. The minute that I know the answer, then it's over."
That said, he credits the makers of hit cartoon Despicable Me 2 with helping him, well, get over himself. It was they who asked him to write the straight up-and-down ode to joy that has relit his career.
"With Happy I was too busy trying to please the producers and the directors and writers. And it worked, because had I been trying to please myself, I would have overshot. And it would have been just like tastemakers' music only. But because I was trying to open myself up to go beyond what I thought was appropriate, and add more intention into it - which was to try and make Gru, the evil protagonist of Despicable Me, happy - I needed to figure a way to make him [happy] on an ultimate level. A relentless level."
Pharrell also had a hand in writing the McDonald's I'm Lovin It jingle (he also worked at the fast food restaurant as a teenager, and lost his virginity to a co-worker). Is he proud of the jingle?
"I'm proud of everything that I've ever done. Even my mistakes. Because without the mistakes there are no lessons. I'm appreciative of my journey, I really am. I'm appreciative for all who contributed to make this path. To get me to this place. They're all just as essential as any tiny little thought that I could have ever had."
All the collaborations - Britney, Madonna, Beyonce, Mika, Jamie Cullum, Usher, Gwen Stefani, to name a top-of-the-head handful - have all given him something. Not working with Jackson is not a sadness, "because we're provided with circumstances that we deduce the lessons that are there for us to learn, and you have to be grateful for those".
That said, "I always wanted to work with Oasis."
Would he work with U2? "Fuck yeah!" he exclaims in a rare burst of volume (it's the only time he swears). "Hell yeah. Who wouldn't?"
As much as he's good at being a solo pop star (and not just because he possesses a sloe-eyed smile to die for), "I love sharing the spotlight. That's what it's for. It's like sunlight, right? It's not just for you and me. It's for everyone. There's room under the sun for everyone. I get a joy out of sharing the light."
Does he get as much buzz from fashion as music? "Sure. You have five senses, and for every sense there's an art form. It all coincides. For each sense there's a sub-modality." Now, super-smooth Pharrell is embarking on another silver-tongued spiel.
"For hearing, there's music. For visual, there's so many things - sculpture, design, drawing, painting. That could go on and on and on. For taste, food, the culinary arts. That's gustatory. For olfactory, which is the nose, there's fragrance. I just did one with Comme Des Garcons. It's called Girl."
What are the signature notes?
"It's mostly wood."