A year ago he was just a plummy former army captain with an odd falsetto. James Blunt's album Back to Bedlam had sat untouched on record shop shelves for months while his singles had failed to make the merest dent on the chart.
A mere 482 people bought his album during its first week of release and even they might have struggled to pick out the feather-haired, artfully stubbled musician in a line-up of twenty-somethings. Yet this week he stands on the brink of cracking the world's biggest music market, the US - a Herculean achievement which has eluded such UK stars as Robbie Williams and Oasis.
In the next few days he is predicted to cap his success by topping the US singles chart, making him the first British act to do so since Sir Elton John with "Candle in the Wind" in 1997. He already sits at number two with the track "You're Beautiful".
Blunt's astonishing rise has been pushed by an unlikely champion, the Hollywood actress Carrie Fisher, known equally for her starring roles in the original Star Wars trilogy as well as her battles with drugs and years of therapy for manic depression.
Three years ago Fisher gave him a home, fed him soup and acted as his therapist. Since then, she has spread the word about his songs to anyone who would listen. So how did this 28-year-old former public schoolboy (Harrow, followed by Sandhurst), who served in the Household Cavalry, guarded the Queen Mother's coffin and served in Kosovo, hook up with an American icon?
It was while Fisher was visiting London that the two were introduced by Blunt's then girlfriend Dixie Chassay, whose family are long-time friends of the actress. When it transpired he was heading to LA to record for an American-based label, she offered to let him stay at her Beverly Hills home.
Her house, she joked, is a "guest house for wandering Brits". For a couple of months they kept their distance, but soon forged a close friendship.
In an interview with The Independent on Sunday she said: "He'd never been to therapy and I've had enough for both of us, so we started talking quite deeply about his time in the army and the kind of impact that had had. And so on. So I was kind of his shrink/landlady."
"We became very, very good friends by the end. He is a good person and he was very good to me when I had a friend pass away. He's a really good soul. This was someone for whom I became a therapist, bear in mind. There was a lot of transference. I still talk to him all the time.
"I played his music to all my friends that came over, whatever celebrity crowd I could muster at my bungalow. I thought he was very good. I actually helped name his album. He didn't know what Bedlam was before I told him."
His five-month stay at Fisher's vast home, which once belonged to Bette Davis, included a spell of recording in her bathroom where she keeps a piano. It earned her a credit in the album sleeve notes.
Recalling his stay, Blunt has said: "Carrie fed me soup, showed me old movies and put a cardboard figure of her in Star Wars outside my room to protect me."
Last week the dreamy-eyed Blunt was continuing his charm offensive in the US with a showcase performance at a party at LA's House of Blues attended by music industry executives and showbiz stars who were in town for the Grammys, America's biggest music bash. Among those who attended his show were Robbie Williams, singer Shakira, Friends star Matthew Perry and actresses such as Mischa Barton from The OC and 24's Elisha Cuthbert.
But Blunt is cool about the need to make it in America, despite his breakthrough: "I'm not really trying to break the US. If it's not broken, don't fix it. I'm just trying to have some fun and learn something, and hope to make a connection. Musical success is not about how many records you've sold, it's how strongly you connect with people."
The connection has clearly been made. His album has now gone into the top 10 and when he returns to the US next month, he will tour as the headline act rather than in the support slots he has been used to.
Back home in the UK, however, where he has just begun a national tour in Glasgow on Friday, his success has not been without detractors. Blunt's name is now synonymous with a kind of wishy-washy dullness, despite selling more than 2.3 million albums in the UK alone last year and six million worldwide. Perhaps it is due to the ubiquity of his delicate single "You're Beautiful", which was the most played track on UK radio in 2005.
The Sun said of him last week: "Exciting. Unpredictable. Energetic. Sadly, none of these are words associated with James Blunt." Paul Weller is reported to have scoffed at the idea of a duet with Blunt at this Wednesday's Brit Awards, saying: "I would rather eat my own shit."
Blunt - born Blount - has a strong military pedigree and his tongue-in-cheek official website biography (written by Fisher under the pseudonym The Landlady) says his family has "served in one kind of army or another since 995AD".
Yet he harboured musical ambitions from childhood, taking up violin and piano and graduating to the guitar as a teenager. His first exposure to pop was a Queen album when he was a boarder at Harrow.
He gave up military life four years ago to make a go of his music. He had already performed odd shows, including one at Water Rats in King's Cross where Oasis made their London debut, while still a serving officer.
Yet for a man who has racked up such astonishing sales and is up for five Brits, even landing a record deal took some perseverance. He had quickly signed a publishing contract with EMI on the basis of a three-track demo, but labels were reluctant to commit and he was eventually signed by the songwriter/producer Linda Perry for her label Custard. That in turn led to a UK deal for his songs of love, loss and even allusions to his army career in "No Bravery".
Music executive Guy Moot, who signed him to EMI Publishing, said: "We tried hard to get him a deal, but at the time we signed him he couldn't get arrested in the eyes of the record labels, which can sometimes be the way.
"But why people over here keep knocking his success I really don't know. If anyone could see the schedule he is on they would realise how much work he has put in. It is just back-to-back with TV radio, press and performances. You work bloody hard to get to the level he has. It's not like the Seventies where you jet in, play three shows and conquer the country."
Paul Rees, editor of music magazine Q, said: "It's really easy to give him a kicking but he does what he does very well. If everybody could write songs that cross over to that many people they would be laughing."
The critics: How beautiful is 'Beautiful'?
"A cursory listen to Blunt's album confirms that 'You're Beautiful' is no solitary lapse of judgement, but part of a sustained campaign of clichés, mockneyisms, empty sentiments and baffling metaphors."
JEMIMA LEWIS, The Guardian
"Blunt may capture lots of hearts if mainstream radio takes a fancy to him. Mostly, though, this music, meant to be unabashedly heartfelt, feels unbearably saccharine."
ROBERT HILBURN, Los Angeles Times
"For people who like Coldplay but find them a touch abrasive, there's British singer-songwriter James Blunt."
"I'm not being an arse for the sake of it but are you telling me that James Blunt and KT Tunstall are a soundtrack for your life? Fuck off. James Blunt? I'm sorry, but fuck off."