When an audience member told Emmylou Harris it had been 20 years since her last Billings concert, it took the singer by surprise. "I guess time flies when you're having fun," she said.

No explanation necessary.

From the opener "Easy From Now On," Emmylou and her Red Dirt Boys looked like they were having fun -- or at the very least, looked completely comfortable -- as they chimed through nearly two dozen songs spanning the singer's legendary career during a nearly sold-out show at the Alberta Bair Theatre Tuesday.

Along the way, Emmylou demonstrated why she's one of the best interpreters of other people's music of any genre.

First up was a spirited nod to her mentor Gram Parsons with "Return Of The Grievous Angel," a song on which she sang harmony vocals more than 35 years ago. Next, she brought whoops from the ABT crowd as she sang the opening lines to Townes Van Zandt's "Poncho and Lefty."

Off and running, Emmylou proceeded with a mix of recent material from her latest album, "All I Intended To Be," and early hits such as "If I Could Only Win Your Love" and "Two More Bottles of Wine."

She covered Tracy Chapman with "All That You Have is Your Soul," and paid tribute to her father with "Bang The Drum Slowly," a tune she co-wrote with Guy Clark.

The biggest cheers of the night came after Emmylou and the band circled around a lone microphone for an 4-part vocal and bass arrangement of The Country Gentleman's "Calling My Children Home."

They finished the set with a Buck Owens standard, "Together Again," and her foot-stomping hit written by Rodney Crowell, "Leaving Louisiana In The Broad Daylight."

For the first of her two encore songs, Emmylou reached into the Townes songbook again for "If I Needed You." Afterward, she openly wondered why she gravitates toward sad songs - "I mean, I had a happy childhood," she joked - then left the ABT crowd humming happily on its way home after a Tex-Mex-flavored version of The Drifters' "Save The Last Dance For Me."

Buddy Miller, a frequent collaborator with Harris and country/Americana legend in his own right, highlighted his set with two duets with Emmylou, "Wide River to Cross," and "Don't Tell Me."

He also reprised his role as a lead guitarist for Harris' backing band, which also featured Chris Donohue on bass, Bryan Owings on drums, Rickie Simpkin on fiddle and mandolin, and Phil Madeira on keyboards, guitar and accordion.

Setlist:

• Easy From Now On
  Return Of The Grievous Angel
  Pancho and Lefty
  Red Dirt Girl
  Sailing Round The Room
  Even Cowgirls Get The Blues
  Strong Hand (Just One Miracle)
  If I Could Only Win Your Love
  Two More Bottles of Wine
  Making Believe
  Goin' Back To Harlan
  All That You Have is Your Soul
  Tulsa Queen
  Green Pastures
  Born To Run
  Band The Drum Slowly
  Shores of White Sand
  The Pearl
  Calling My Children Home
  Together Again
  Leaving Louisiana in the Broad Daylight
  Encore:
  If I Needed You
  Save The Last Dance For Me