Even though KT Tunstall's latest effort, "Drastic Fantastic," was released only last year, the Scottish singer/songwriter tells Billboard.com ...

Even though KT Tunstall's latest effort, "Drastic Fantastic," was released only last year, the Scottish singer/songwriter tells Billboard.com she's already reworking the material for her upcoming stateside tour in a fashion that could influence the direction of next studio effort.

"Basically, the kind of new setup, which we've never done before, is inspired from the film we did for the deluxe version of 'Drastic Fantastic,'" Tunstall says. "I'm friends with Alex James, the bassist from Blur, and he lives in this beautiful farm land in Oxfordshire and we went there and recorded a campfire set.

"So we had all of these microphones hidden in our clothes and recorded this by a fire," she continues. "We just loved playing that way, and we thought it would be a great twist of, after having done a kind of electric rock-based album, to then go back to where it started with the kind of acoustic thing."

Tunstall's next American leg, which is billed as "The Campfire Tour," begins May 3 in San Diego. She says the show will feature all acoustic instruments -- double bass, xylophone, glockenspiel, mandolin and guitars.

While Tunstall plans on touring through the fall before hitting the studio next winter, she's already thinking about a more folk/blues approach for her next album. She expects to play at least one new song, the Bob Dylan-influenced "Turn Into You," on the upcoming tour, but has reservations about giving her fans too much unreleased material.

"There are a couple of new songs I'd like to play, but I have to say while I love the Internet, the one thing I moan about is you can't really test-drive songs anymore," Tunstall says. "Because as soon as you play it, it's up there, and I don't really want it to be up on the Internet when it's not finished.

"So you get kind of nervous about playing new stuff," she says. "Also, I want the new album to be a surprise and not for everyone to know the songs already. So it's kind of juggling with that as well and making sure that if you're going to give songs away, you know that's going to happen."