And you thought the swan dress was crazy.

I agree, instruments are so over.

Bjork Voices "Medulla"

New album to consist solely of vocals

"Instruments are so over," says Bjork of her new, purely vocal album, Medulla, due out late August/early September.

"I think this was probably the most intuitive album I've done," she continues. "I had to use ingredients that I trusted, like my voice, my muscles, my bones. I couldn't really use all the other stuff."

Rahzel of the Roots -- known as "the Human Beatbox" -- supplies the percussive bass line for a majority of the songs, and the album also features collaborations with Inuit throat-singer Tanya Tagaq and former Faith No More frontman Mike Patton. The sound is primitive, full of brooding menace on "Where Is the Line" and soaring, breathy romance on "The Pleasure Is All Mine."

Following Medulla's release, Bjork will continue working in the studio rather than go on tour.

"Every album I've done, the minute that it's done, I feel really lubricated and, like, 'Wow, now I can write an album in five minutes,'" she says. "And I just want to find out if that's just a fantasy or if it's true."