Haim set sights on big time after winning BBC's Sound of 2013
Dong! Backstage at the O2, it's just struck celeb o'clock. As Day & Night loiters in a chilly reception area, Florence Welch tiptoes past, wearing a wide-brim hat vaster than one of Saturn's outer-rings.
Upstairs, meanwhile, await hottest-newcomers-in-rock Haim: three hayseed LA sisters whose hype rating is so off-the-charts they are probably being blogged about on other planets.
"It's crazy," says lead singer and middle sibling Danielle, when the interview finally gets under way following in interminable spell of heel cooling (Chinese dinners required scarfing, we understand). "If you told us a year ago all this would be happening, we'd have laughed."
"It's definitely better than not having anyone talk about you," chips in youngest Alana.
"Even if people weren't saying stuff about us, life would be great," adds Este, the eldest.
"I mean come on – I get to tour the world with my sisters."
In a few hours the Haim girls – pronounced 'Hime', it's the family name as well as group moniker – will step in front of 14,000 or so mildly raucous fans for their first ever Irish date.
To be fair, a fair wedge of those in attendance are here for the main act, the aforementioned Flossie. Still, the love coming Haim's way will feel genuine and, as they romp through 40 minutes of harmony soaked, 1970s-style Cali-pop, it will occur to you that here is a band on the threshold of something huge.
In their dressing room beforehand, they're excited, if not quite pinching themselves. And why wouldn't they be? Haim have already headlined their own show at London's 3,500 capacity iTunes festival, been the subject of rhapsodic tweets from Katy Perry and Azealia Banks (talk about covering your bases) and received approving nods from Arctic Monkey Alec Turner (not a chap given to cheap flights of rhapsody, it's fair to say). Their world is moving very fast and sold-out support dates no longer leave them winded and starry-eyed.
Seated in a semicircle, their father (who doubles as tour manager) drifting out of ear-shot, they are full of surprises.
Alana is the saucy-mouthed live-wire. With her dad around, she's on conspicuously good behaviour. After a few cocktails, you imagine her being fabulously indiscreet.
Occupying the sensible, dependable role is Este. She's the only sister to attend college, majoring in world music as UCLA, and will, if you let her, dominate the conversation, albeit in the sweetest way possible (you'd never guess she tweets, quite acerbically, as 'JizzieMaguire').
Danielle is the enigma, solemn and self-contained where her siblings are giggly and touchy-feely (our conversation ends with a surprise group-hug). With her leather jacket and indie-chick hair, she is also by far the coolest.
You can see why Strokes singer Julian Casablancas, spotting her at a gig in New York (she was playing guitar for Silver Lake alt- babe Jenny Lewis), was smitten and asked her to join his ensemble. She is the one you can't take your eyes off.
"What's great about working with Julian is learning how to use a studio properly," she says. "We always struggled getting our records to feel 'right'".
"We'd worked with these older guys in Los Angeles who said they'd produced Fleetwood Mac's Rumours – that's a joke by the way, EVERYONE in Los Angeles says they produced Rumours. They'd walk in, turn all the gear on, and tell us go record," says Alana. "It never sounded they way we wanted it to. To them, we were just another band."
"Julian is meticulous about recording," resumes Danielle. "He'll spend hours getting a single aspect of his sound right. You can hear that on The Strokes' records. They have a very specific aesthetic. I recorded some B-sides with him. What I learned was that Haim were playing too many shows. We needed to go spend some time in the studio."
Haim's music is pure sun-kissed LA, a drowsy, tambourine- shaking mix of Stevie Nicks, The Bangles and Joni Mitchell.
Far from coming of age in the hippy hang-outs of Laurel Canyon or Venice Beach, however, the sisters are from San Fernando Valley, a suburban sprawl contiguous with LA proper.
It's where you go to buy a house and raise a family – though, bizarrely, it is the home to the US porn industry too.
"The rent is so cheap you can afford to have a movie studio there," says Este. "Ever since Boogie Nights , the area is notorious. It isn't like you see porn stars walking around the place.
"That is out of sight. The valley is where a lot of the really famous recording studios used to be. It's changing. Everyone has home studios and the old studios are starting to shut down."
A potted biography of Haim begins with them growing up in San Fernando, the children of Donna and Moti.
In their teenage years, they attended LA High School for the Performing Arts, a prestigious stage academy which they describe as the West Cost's answer to the Fame college.
"Josh Groban went – he's kind of the biggie," volunteers Este.
"And Fergie," says Alana. "Nobody is quite sure for how long. It's one those unknowns – 'did she, or didn't she?"
Alongside their studies, they were earning their spurs as a live outfit, playing covers with their parents as – yes, they do know this is the worst band name ever – Rockinghaim.
"We could have made a LOT of money," says Alana. "We were constantly offered Bar Mitzvahs. They pay like, three grand a night. That's a circuit you get sucked into.
"We had no interest. We performed in county fairs the length of California."
Haim, we suggest, were chronic sufferers of 'cool parent' syndrome. If your folks are sufficiently hip to play alongside you in a band, how do you rebel? Study accountancy?
"They could be square," says Este. "We still had curfew. It was like – 'you can go out and play rock and roll. But you've got to be home by midnight'."
"Our dad has three daughters, " says Danielle. "He's a little on the protective side.
"I still have my curfew, adds Alana. "And I'm, like, 21."
Haim are Jewish and observe the religious calendar, largely because they love the food and the way it makes them feel closer as a family.
It's a facet of their lives they take absolutely seriously. At the iTunes Festival, they went on after a 24-hour fast.
Miraculously nobody passed out.
"Because the gig was on Yom Kippur, we had not eaten all day. Thank God the adrenaline kicked in," says Danielle. "The first drink of water I had was just before we played. Afterwards, it was like 'get out of my way I have to get to catering!' I think we ate them out of all their pasta."
Giggly and good-natured, they are visibly at home in the limelight. In their six months of quasi-fame, the downsides have been few. The only thing that truly irks them is when people mangle their moniker, so to speak.
"Everybody assumes we're somehow related to Corey Haim," says Alana, referring to the cheesy late 1980s heartthrob (who died of a prescription drug overdose in 2010 aged 38).
"Which is cool so far as it goes. Great actor."
"The problem is everyone thinks our names are pronounced the same," says Este. "So we are constantly called Haym, rather than 'Hime'. It's annoying. But yeah, Corey Haim ... a pretty cool guy. We're definitely more Corey Haim girls than Corey Feldman ones. RIP, dude."
Haim's new single is Don't Save Me
Day & Night