At 11pm on a warm Monday night, Paolo Nutini - one of the rare 20-year-olds in possession of traffic-stopping good looks, a double platinum-selling debut album and, now, a Brit nomination - is wrapping up an "awesome wee gig" at Portsmouth's Wedgewood Rooms.
The roars that greet his final number, a cover of Gnarls Barkley's "Crazy", will be no more than a punctuation mark in Nutini's scrapbook. Since he burst into the world's musical consciousness in May last year with a maudlin, soul-infused single called "These Streets", such scenes have become ordinary features of his now extraordinary life.
By 1am, he and his three-piece band have jumped on to their luxurious tour bus, helped themselves to some chilled, bottled refreshment and made use of the showers and bunks on board. At 3am, they arrive at a central London hotel. And early, too early the morning after the night before, they make their way groggily to the ITV studios, where they are booked to perform one song for The Sharon Osbourne Show.
Now it's mid-afternoon, and Nutini, with his drummer Jim Duguid, are at Olympic Studios in Barnes, where Hendrix and Zeppelin and the Stones have immortalised themselves. Kylie is downstairs. Nutini looks on as 22 string players pack up after recording a backing track for one of his songs.
Nutini is supposed to be speaking to The Independent behind the tinted windows in the back seat of Atlantic Records' Mercedes as he travels to his next gig in Oxford. But it's not going to happen; his posture, unmilitary at the best of times, has depressed into a languid slouch, and his eyes, red from lack of sleep or excess or both, creep out from under his supermodel eyelashes. The only press he wants right now is a cold and soothing flannel.
"Do you mind if we don't?" he says, in his friendly, slurred Paisley brogue. "If ah talked to you now, you'd think I was brain-dead. I'm going to sleep in the car and see you in Oxford." When we finally sit down together, backstage at Oxford's bijou venue, the Zodiac, Nutini seems less agitated. The sound-check is over, and now all he has to worry about is what he's good at: performing. "I'm sorry about before," he says, relaxing with a Corona and a roll-up. "It's all just been a bit mad."
An understatement. Nutini, who received the ultimate 18th birthday present in May 2005 when he signed to Atlantic Records, has had a hell of a ride. His album, These Streets, a Ken Nelson-produced medley of heartache ballads and rockers rich with the influences of American 1960s and 1970s soul, went to No 3 in the album charts in its first week. He has gigged all over Europe and America. He has supported The Rolling Stones. He has had far too little sleep.
"It's hard, man," he says. "Hard to write anything new when you live like this. I like to record something pretty much as soon as I have an idea for a song, but I'm on so many buses I have to record on my mobile. I can't wait to go home for a wee while, get on the laptop and get some stuff down."
Home, though, is a hard place to find. Nutini admits: "I don't really live anywhere." He stays at his parents' house in Paisley, where he grew up, about two or three days every month.
"It's so important I go back," he says, dolefully. "As I'm getting older, I work out what I want and what I need. And I just need to go home and see the people I love and write."
What Nutini needs, it seems, is not just love but material. One reason his debut is so charming is precisely because it is an honest recording of an ordinary existence. That existence is now over. And Nutini needs to know where the next songs are coming from.
"I don't want to slip into Johnny Borrell mode," he says. "I don't want to be singing that there's nothing on TV, nothing on the radio. I like Razorlight, but the first two tunes on that album [Razorlight], good as they are, concentrate on the same subject. I know where he's coming from - being away and stuff - but it's not for me."
It is at these moments that Nutini seems painfully boyish - fragile, even. He has, one has to keep remembering, only just turned 20. But, just as he pines for home comforts, there is another part of the young man that's loving the rock'n'roll dream into whose grip he has so palpably fallen. He is, by his own admission, a "wee, hippie, stoner kid". No sound-check or gig, meanwhile, is complete without the demolition of several lagers.
This party hard, work hard lifestyle caught up with him on the eve of his biggest moment, performing on the main stage at T in the Park. In July, The Scottish Sun plastered Nutini across its front page, joint in mouth, with the headline "Wasted Talent" and a quote attributed to the singer that he was going to "be getting stoned off my fucking face".
Nutini denies the quote - "Honestly, who would say something like that?" - but he makes no pretence about his predilection for green. "The only thing that upset me about that story, really, was that my mum saw it, and she was upset," Nutini says. "I thought it was sort of hilarious. I mean: shock, horror, 19-year-old smokes weed! I don't know why [The Sun] would want to do that to me, though. It was the day before the biggest day of my life, and they tried to ruin it for me. They said I was advocating to kids. How can I be advocating to kids? I am a fucking kid!"
Suffice to say, Nutini finds his unsolicited status as a role model a strange one. His only interest, it seems, is making a great noise and enjoying the ride he finds himself on. And, when he's quizzed about music, Nutini is unusually eloquent. So how does he feel now about an album he recorded what must seem a lifetime ago?
"I'm about 70 per cent happy with it," Nutini says. "Everything you hear on the record is somewhere between what I wanted and a radio edit. I'm proud of it, but I'm learning as I go along. I'm getting to think the more simple, bare, everything is around me, the better I sound. And all the songs I'm writing now are like that - simple chords, simple melody."
That formula serves him well in the Zodiac, as 400 fans press towards the stage, leaning in to hear the cadences and phrasing of his Golden Virginia voice. With no string section - just guitar, bass, drums and keyboard - the sound is spectacular. There's high emotion, too; on "Autumn", a song about the death of his grandfather ("Nonno", as Nutini calls him), the vocals are interrupted by a reverberating sob. When Nutini makes it to the end of the number, he gives the microphone a kiss. He must have sung "Autumn" 200 times by now, but tonight, it's like the first time all over again.
The crowd, as they always do, love the set. And, at midnight, 45 minutes after the gig, 30 or so fans try to cram into Nutini's tiny dressing room to get their piece of him. Nutini chats to people he's never met before and will never meet again, eyes turning redder by the minute. As he does so, a camera crew jostles through and places a boom mic over his head. Nutini looks nonplussed. But his bassist, Michael McDaid, sighs and turns to me. Is this normal, I ask?
"Aye," he says. "Just Paolo, the band, and one or two of our closest friends."
'New Shoes', from the album 'These Streets', is released on 19 February. Nutini's next UK tour starts on 17 April (www.paolonutini.com)