Singer/songwriter Leslie Feist made a surprise appearance last night (Sept. 10) at Kings Of Convenience's sold-out show at New York's Bowery Ballroom, joining the Norwegian duo for the songs "The Build-Up" and "Know How."

Feist sang "The Build-Up" completely un-amplified from the balcony of the venue, while "Know How" found her harmonizing with Erlend Oye and Eirik Glambek Boe from onstage. Feist appears on the studio versions of both songs, which can be found on the 2004 album "Riot on an Empty Street."

The show was Kings Of Convenience's first appearance in New York since the tour in support of that album. The group was in town to preview material from its long-awaited new release, "Declaration of Dependence," due Oct. 20 from Astralwerks. Highlights of the new tracks included the jaunty single "Mrs. Cold," the hushed opener "24-25" and "Me in You," which found Oye harmonizing in his seldom-used upper register.

The duo frequently joked with the audience about everything from the long layoff between album releases, spilling espresso on each other and how the constant clicking of digital cameras was actually louder than the band's stage volume. Oye and Boe also lightened the mood with a cover of Leslie Gore's 1960s classic "It's My Party."

Kings Of Convenience begins a European tour Oct. 3 in Stockholm. The group will be back in the States for performances in early 2010, with details to be announced.