'This is a song by Elliott Smith," Seth Avett announced Saturday night with complete sincerity as he stood next to Jessica Lea Mayfield on the Keswick Theatre stage. For a duo touring in support of their coming album Seth Avett and Jessica Lea Mayfield Sing Elliott Smith, this introduction before each song should have been overkill.

But although Avett may have been stating the obvious, his collaboration with Mayfield breathes new life into Elliott Smith's catalog of forgotten gems. With each introduction ("This song is by Elliott Smith and is called 'Between the Bars' " and "We're going to play you another Smith tune, this one is called 'Memory Lane' "), the collection of somber waltzes by a man who took his own life more than a decade ago was resurrected.

Avett, 34, the youngest of the Avett Brothers band, and Mayfield, 25, the songwriting prodigy with a space twang, bonded over their love of Smith and began work in 2011 on an album of cover songs. Because of their separate, equally busy, touring schedules, they met up sporadically in houses, hotels, and recording studios across the country and recorded 12 of Smith's songs that clearly have left an impression on both artists, emotionally and lyrically.

Mayfield, in a black sequined minidress, and Avett, with a nonstop jug-band bounce, were joined by upright bassist Paul DeFiglia for a 90-minute set containing minimal banter. The evening featured a mix of the Smith tunes from their covers album, songs from their respective solo projects, and songs that show a direct lineage to Smith and his own musical influences. On such tunes as "Ballad of Big Nothing" and "Pitseleh," the duo alternated lead vocals and harmonies, revealing a rich texture to songs that originally had multitracking layers of Smith's papery voice. Each one grew beyond its original potential - still recognizable, but with new ownership. Both Avett and Mayfield have powerful voices that carry the words and melodies of familiar songs to new levels. In a near-perfect interpretation of Bob Dylan's "Just Like a Woman," Avett warbled, whispered, and wailed, Mayfield sang backup, and an enthusiastic audience member screamed "Yeah!" at the top of his lungs in support of this spirited collaboration.

The only distraction of the night came from an unfortunate piece of scenery that dwarfed the stage and added confusion to music and musicians better served by a bare stage and a velvet curtain.

Looking past the cluttered stage, the evening was a celebration of Smith and his posthumous legacy. As Mayfield and Avett sang so genuinely, "It's just a fond farewell to a friend."