Stephanie Dosen is feeling a little under the weather - and who can blame her? Stepping into the seriously imposing shoes previously occupied by Shara Nelson, Tracey Thorn and Elizabeth Fraser would be enough to make anyone turn a little green around the gills.

It eventually transpires that it's only the flu that's ailing the Wisconsin-born singer and songwriter, but she admits that when she got a phone call out of the blue last year inviting her to become the latest in a long line of heavyweight female vocalists to work with Massive Attack, she "had to sit down mid-shopping spree" to absorb the shock. She has since recovered her composure and is now midway through helping the notoriously leisurely but much-lauded Bristolian musical collective (who will also be curating this year's Meltdown Festival at London's South Bank Centre) make their new record.

"It's really good, really collaborative," she says. "I come in with stuff and we work through it. We bounce melody ideas and lyrics back and forth, picking things apart to hopefully make it better. The longer you work on things, the more you think, Oh, we could try this or try that,' so we're really experimenting and taking our time."

Like a number of other high-profile artists, among them Jools Holland and Swedish indie-folk star Jose Gonzalez, Massive Attack became smitten with Dosen's second album, A Lily for the Spectre. Released last summer, it fulfilled the wayward promise of her self-released debut, Mice, Ghosts and Vagabonds (which, she happily points out, is still available via her website after her father recently found a load of old copies in a cupboard).

An album of delicate, unusual and often beautifully crafted songs, A Lily for the Spectre is pitched somewhere between folk, indie and melancholic pop, all topped off with Dosen's pure, clean, ethereal voice. In both song and appearance, she comes across as an almost pre-Raphaelite creature, all long white dresses and flower-strewn tresses (plus, occasionally, wings) - the kind of artist for whom the word kooky could have been specifically coined. She describes her songs as "music for weary sailors and tangled mermaids", claims to have grown up on a peacock farm and written her first song for a swan and a fox, and publishes MySpace blogs about moths and owls.

I can't help wondering whether there's an element of contrivance in all this. "Well, everything I see I like to put curtains on and kind of romanticise," she admits. "But we did have peacocks wandering around the house when I was young, and we always had a million animals. I spent a lot of time in the forest, making a little house out there and hiding in the trees and stuff like that. It's all in there. My parents owned a pizza store when I was really small and if a customer came in I had to hide under the desk; I spent a good part of my childhood under there. I still have that in me - if someone rings the doorbell I have this urge to run and hide."

A strong and compelling sense of this little-girl-lost quality is evident in her music, which often gives the impression that Dosen exists in some off-kilter, slightly unsettling fantasy land entirely of her own making. She appears, however, to be reasonably well grounded in real life. She now lives in London - "I love it" - and in concert she cuts a far from reticent figure. "I'm a little bit chatty," she nods, smiling. "I try not to be, I try to be dark and mysterious, but I'm just not. I can't help but see the absurdity of it all when I'm up on stage. It kind of cracks me up to play live in the first place. I get quite giddy and silly when I'm out there."

At school in Wisconsin she would put on the occasional show, but after leaving home she hit the clubs of Milwaukee and Chicago with a vengeance. Then, rather incongruously, she moved to Nashville in search of her big break, despite the fact she doesn't play country music.

"I worked there for a couple of years trying to get something going, but everyone there is trying to do the same thing," she says of the experience. "You're all just a bunch of little fish swimming around and bumping into one another. Everyone was like, Wow, you're really good, but do you do country?' I thought, hmm, they told me nobody was going to say that! There is an underground, non-country scene in Nashville, but it's not the style of music I'm doing. It was kind of hardcore and death metal."

Despite her avowed fondness for skate-punk, the notion of Dosen turning her delicate hand to death metal is a mind-boggling one. She says she listened to a lot of classic rock such as Pink Floyd while growing up, and has a soft spot for the Smiths and the Cure, but it was the "big folk revival of the early nineties" that opened her up to the music of Tracy Chapman, Sinead O'Connor and Suzanne Vega, and inspired her to pick up a guitar and write.

Her music has certainly evolved beyond that starting point. She ploughs a less straightforward folk furrow than Vega or Chapman, and although there are echoes of O'Connor in the timbre of her voice, she has just one true vocal idol.

It transpires that working with Massive Attack isn't the only connection between Dosen and Elizabeth Fraser, the celebrated vocalist with now-defunct Scottish alternative-rock superstars the Cocteau Twins. Dosen is signed to Bella Union, the label run by ex- Cocteau Twins bassist Simon Raymonde, and openly reveres his former group and their notoriously reclusive singer. "The Cocteau Twins are my all-time number-one band, which I'm sure people can hear in my voice," Dosen says. "Liz was like my teacher, really. I'm still in such awe."

Before she meets up again with Massive Attack, there's another creative union to enjoy. On Thursday Dosen is appearing with Jose Gonzalez at London's Bush Hall as part of the iTunes Festival; they'll play a few songs separately and then perform together at the end of the evening. "I'm his biggest fan and I'm getting to work with him, so I'm incredibly excited," she says.

Having delivered a critically acclaimed solo album and bagged a recent TV spot on Later with Jools Holland, many fledgling artists might be reluctant to devote so much time to collaborative projects. Dosen, the very essence of a free spirit, has no such qualms. "I'll work on anything that strikes my fancy, I'm very random about it," she says with a grin. "I don't get real rigid or strict with myself. I just go and do it."


Stephanie Dosen plays the Ark, Edinburgh, on February 27 and King Tut's, Glasgow, on the 28th. A Lily for the Spectre is on Bella Union.

 www.stephaniedosen.com