Fresh from a filming session at Abbey Road studios, Florence Welch is in a chirpy mood.
She has good reason to be – her album has debuted in the charts at No.2 and, alongside La Roux, she's fast becoming the face of British music in 2009.
Yet it seems the 22-year-old south Londoner has herself been somewhat taken aback by the speed of her rise from indie poster girl to mainstream star.
"I'm just pleased to have made an album in itself," she says. "It's a strange feeling (sitting behind Michael Jackson in the charts), but it's like I never expected to be an artist. I've never had a single in the top 10. To go in at such a high chart position, it's quite amazing. It's an abstract thing. These things are not real."
The most striking feature of Lungs is, of course, Florence's voice. Big and bold, with an impressive range, it's well equipped for the high drama of songs such as Kiss With a Fist and Rabbit Heart (Raise It Up).
Indeed the whole album sounds very much like a statement of intent. "I think so," Florence agrees. "It was like I wanted to make something that was beautiful and dark at the same time – also I wanted to make something epic, something that had an intensity to it. I did just want to make something massive."
Critics have noted the influences of Kate Bush, Alice's Adventures in Wonderland and the Pre-Raphaelites on Lungs. For Florence, though, the main inspiration was "not being able to play a musical instrument".
"My main influence is being a completely inept musician," she says self-effacingly. "I think the whole album is about learning to make music bit by bit, going from instinct rather than from any training."
The songs themselves evolved over the last couple of years through live performance. Now, at last, she feels she's finally got them nailed. "It's good. I feel like I've finally got something solid. Now we are evolving them from the album.
"Playing live we were finding different ways of getting them across. You can't do it exactly the same way as it is on the album. Before, we did the songs differently each time. There was no set version. Now the album is done we are having to learn them again.
"It's all quite shambolic, really," she laughs. "We just throw everything at it and see what sticks."
But success in the music industry often brings attendant pressure to do things in a certain way, particularly when you're working for a major label. Florence hopes she can maintain her creative independence.
"Hopefully I think I will just carry on being as useless a musician as possible and carry on making things based on instinct rather than training. Eventually I will be able to play something well but following your gut instinct with music is the most important thing, following what feels natural rather than any kind of stricture."
Lungs's success – 100,000 copies in the UK and counting – has also thrown the spotlight on Florence's boyfriend, Stuart. Many of the songs were written in repsonse to the break-up of their relationship. Does it feel strange singing them now they're back together?
"He prefers me not to talk about it. It's funny then singing about it. It's easier to hide things talking about them rather than singing about them...
"It's kind of complicated," she muses. "What relationship isn't complicated?"
Despite her newfound musical fame, Florence remains something of an artist at heart. Her mother, Evelyn, is a professor of art history, specialising in the Italian Renaissance, and Florence herself studied at Camberwell College of Arts.
"I'm always drawing," she says. "I've got such a frantic brain. If I'm not producing something I go inward and have negative thoughts. The way out of things spiralling is to do something, whether it's drawing or a piece of music. You feel like you are saving yourself from the encroaching doom."
Besides, Florence's creative sides regularly cross-pollinate. "When I was growing up, going to art college parties, performance and art was an important thing," she says. "Making shapes with my body on stage is important. I'm always thinking about what I'm doing. I'm either taking off or being dredged up."
Fans can look forward to another of her famous stage dives when she appears at Leeds Festival on Sunday, August 30. "I f***ing hope so!" she says. "That would be fun. I love crowd-surfing. I was too scared to do it when I was like a little punk. Now I'm older I'm a bit more adventurous."
Following in the wake of Florence's eye-catching performance at Glastonbury, it's expected to be another highlight in what is turning out to be a memorable 12 months. Did she think, back in February when she won the Critics' Choice Award at the Brits, that 2009 was going to turn out to be her year?
"I don't know. It was more nerve-wracking than anything else. I felt out of my depth. You can never tell the way things are going to go. No-one can tell the shape of their fate. You have to sink or swim. Hopefully I'm swimming."
With another gong possibly in the offing – Florence and the Machine are the bookies' favourites for this year's Mercury Prize – many would say she's right.
Tickets for Leeds Festival and Florence and the Machine's gig at Leeds O2 Academy on September 21 have sold out.
Click here for more